The owner passed away recently...no longer to offer services. I went there today, May 27, 2025...note on the door that the business is no longer. read more

Ripped me off Gave them 300 to check out my Generator. They took years. Gary went in the hospital some and his friend ran the place like a business for a week and got my generator done, now I can't even pay the 1000 for the work and pick it up. To bad that guys not running the business. read more

Gary is definitely one of the most knowledgeable gen techs in LA. He was able to get my RV I'm on short notice and had me running just after lunch. Was very clear along the way on what he was doing / my options / and costs. As long as Gary is in business he's got a customer here. read more

Advanced Generator Service - Gary and Jason putting in work even in the hot LA summer. - Generator Installation/Repair Near Me - Azusa, California

I had my Rv onboard generator serviced back in late May. I've since had 3 summer trips and can report back that the generator is running fine. My 1997 Class A RV with an Onan 5000 generator was having intermittent no start/stalling issues. I called Gary and he got me in the following week. He diagnosed the issue and ordered the replacement parts. For those with Onan generators, the parts can get very expensive, but given the low generator hours on my unit I opted for the repair rather than looking at replacement options. The repair took 2 separate appointments as I also got preventative maintenance work done at the same time. I would definitely go back and see Gary in the future for any generator related issues. read more

Advanced Generator Service - Onan Marquis 5000 generator - Generator Installation/Repair Near Me - Azusa, California

It's no longer in business even though the phone number is active. Verified by going there in person. It's too bad because they were great in my past dealings. read more

Gary runs an incredible operation. I have rebuilt a 1984 Tiffin Allegro Motorhome and wanted to make sure the generator is working in top form. Advanced made this happen. This company knows the Onan-Cummings generators read more

Advanced Generator Service - Generator Installation/Repair Near Me - Azusa, California

See all

Significant generator servicing needed on a deadline along with a late inning fuel pump failure. Gary and Adam stayed late to get the job done. Great job! read more

Gary changed my Cummins Onan 4,000 generator fuel pump using one from CHINA (after market )fuel pump and charged me $1,200. BEWARE !! Furthermore, he altered the fuel pump from CHINA and my generator to make it fit. NOT A TRUSTWORTHY BUSINESS. read more

Advanced Generator Service - China after market fuel pump and Cummins new fuel pump. Gary alerted the after market part to fit my generator . - Generator Installation/Repair Near Me - Azusa, California

I'm so grateful I found this place on yelp:)) Gary fixed my generator for my mobile grooming van, up and running back to work, totally worth it! I highly recommend this place:)) if I could give more stars I would:)) read more

Advanced Generator Service - My Moblie van :)) - Generator Installation/Repair Near Me - Azusa, California

Found this place on yelp... my dad and I were extremely happy with the service. Gary was extremely helpful, nice and was quick to get my dads motor home back to him. Would definitely recommend this place. read more

Great customer service - went the extra mile to service my generator and had it ready when promised. Garry was very knowledgeable and professional. Got what I paid for! Ramirez read more

Gary took a handful of my phone calls as I was stuck on the road in my rv trying to get to Georgia from Cali. He diagnosed my problem immediately with just my explanation of what the generator was doing. Having to pay a service fee, I had a mobile rv guy come out the day before and he couldn't figure out what was wrong but Gary did immediately over the phone. He even took the time to caliper measure the part I needed to find and sent me photos. He did it all for free just to help someone in need. I can't thank Advanced enough for the time they spent to get me going. If I lived remotely close to Azusa I wouldn't take my generator to anyone else. Don't waste your time or your money. Advanced Generator is the best there is hands down!!!! read more

After I tried to repair my generator myself and caused damage to it I ended up at advanced generator Gary spent a lot of hours including 3 hours after closing he stuck with it until all the issues were fixed. I appreciate his dedication and knowledge on the onan generators. Great guy as well thank you Gary I'll stop by and visit when I'm in the area. Thanx again read more

Gary Patton really knows generators! Our ONAN 5500 Marquis Gold just shut down in our motorhome on the way home from a trip...after researching repair places, I took a chance and called Advanced Generator Service and am I glad I did. Not only did he repair and mechanically update our generator, he gave me great tips about how to keep it running in great condition. If ever needed again, I'd go back to Advanced Generator Service in an instant...I highly recommend his generator expertise, and service! G.R. Tooth read more

Gary is the real deal. I purchased a used RV that sadly came with a worthless Generac generator. Now heading in to retirement my goal is to do more dry camping which requires a quality and reliable generator. After hours of searching the internet and reading reviews I found Gary at Advanced Generator. If you are looking for hugs and kisses and chocolates on your pillow he's not your guy. Being an EMS First Responder (Flight Nurse) I so appreciated his 'salty' assessment of what needed to be done and the costs and time required to get it done right. He got the old unit removed and the new unit installed and tested for a very fair price and spent extra time showing me how the new unit worked. I highly recommend this company and will return for servicing. read more

Advanced Generator Service - Generator Installation/Repair Near Me - Azusa, California

I made an appointment for a 500-hour service on my Onan 2500 RV generator. At the time of scheduling we discussed how the location of my particular generator made it difficult to work on, and required the generator to be removed for service. At the time I booked the appointment, I asked about checking valve clearances. I was told that it was included. The quote I received was for $300 labor plus parts. This seemed reasonable, considering the extra work required to remove the generator. I walked across the street to let Gary do his work, and observed him put the vehicle up on ramps and jack the front, not remove the generator but do the work under the vehicle, clean up, complete his paper work, and remove the ramps and jack. Total elapsed time was 45 minutes. The work performed was the following: 1) Change oil. 1 quart. No filter required. 2) Replace spark plug 3) Replace air filter I received a call that my vehicle was done, and walked back across the street to pick it up. When I asked about what he found when he checked the valve clearances, Gary got a little irritated and said he told me that he didn't need to check the valve clearances as they 'never change'. And he claimed to have specifically told me that he would not be checking them. He also claimed to have never said he had to remove the generator. Both False. I think his poor attitude toward me dates back 7 years earlier when he did some warranty work on this generator. He neglected to write down the serial number, and had some difficulty adequately communicating his needs to my wife. He ended up driving to our house and retrieving the serial number himself. This service work was not what I would consider to be 'skilled labor', as in a service which commands a premium service rate. It is something anybody with any automotive hand tool experience could perform quite easily. The billed labor rate of $400 per hour is excessive by a factor of 2x minimum. Penske Mercedes shop rate is approximately $200 per hour, and that is high in the industry. My perception is that I was being punished with excessive charges in retaliation for the serial number incident. So considering the bad attitude and gross overcharging, I would not recommend Advanced Generator Service. I know Gary must be a competent service technician who can diagnose difficult issues. But when it comes to simple service, take a pass unless you like being overcharged. read more

After running well for a couple of years, about a week ago, my generator stopped starting. When the usual troubleshooting failed, I guessed that it might be a bad fuel pump. A bit of research led me to Advanced Generator Service, a Cummins Onan repair service in Azusa California https://www.advancedgeneratorservice.com/. Watching Gary Patton, the owner, chief cook and bottle washer, made me very happy I'd decided against tackling this on myself. He however had the parts, dropped and repaired the generator and had me back on the road no time. So, if you're in need in anywhere in Southern California Gary gets my highest recommendation. read more

I found this place approximately 10 years ago and I have to say it was one of the best finds I've ever found. They understand that my generator keeps my business going and that our CCTV pipeline inspection trucks don't make any money if they're waiting three weeks in a shop for somebody look at them. They are well certified to work on the equipment. They only use oem replacement parts and know exactly what they're doing no shortcuts. I never asked the prices because it doesn't matter for the quality of work that you get from this outfit. I could not stress to you enough how a critical business needs to rely on a service like this to keep their equipment running. he gets my highest respect for the dedication to his business. read more

Gary was very accommodating. He gave me the option of removing the generator (Onan 7000) or fixing (carb and Fuel pump replacement) right there. Pleasant individual. read more

Excellent service, brought a 24ft toy hauler with a non running 5.5 generator at 9:45, got a call at 13:30, picked up at 16:00. Did not have to wait on parts, his quoted price was cheaper then the previous technician who worked on my generator. The 18 months I owned the trailer the generator has NEVER started on the first cycle. I'll be back for service at 400 hours. read more

My guy!! Lol they always get my generator running right! Usually we're only there for maintenance but this last used trailer I bought had been terrorized by rats and needed a whole rebuild! But of course he fixed it with and pretty much got me a new generator for half the price. Always take my stuff there he's the man read more

I originally made an appt to get my 1983 Onan generator fixed in May that did not require taking out of the trailer, since it had open access from both sides and the bottom. Laura the Secretary called and cancelled my advanced appt saying the date was overbooked. It took two weeks to get another appt to get back in. I asked if I could haul it in the night before due to traffic and my work schedule. They refused stating "there is no overnight allowed" even though there are 6-10 parking spots there. (How could car repair places exist with this policy ?). I finally brought it in at 830AM in late May as they said that was the earliest, and that it would be completed that same day. No estimate was given. I had other business to do near the shop, so I stayed out there on that side of town hoping to get it back early. About 1245 pm I had dropped by to check progress. They hadn't started on the unit over 4 hours after drop off. No other trailers were there. I asked "Garry" to check the fuel system, rebuild carb if needed, and get it running well. I had already drained gas, replaced the fuel line hose, installed an in-line fuel filter from tank to fuel pump. I parked nearby within eyesight of the trailer and work from 1-5 pm with a break for lunch. I was finally called about 300 pm with an estimate of $700.! I was blown away with the price and asked for breakdown of parts and labor. Parts $350 and labor $350 he said approximately. I felt STUCK since I wasted a whole day out there when I could have just dropped it off at another business and picked it up next day. But because he strung me out 6 hours before the repair estimate and it HAD to be picked up at 5:00 I felt "over a barrel". The bill was $680.00. He showed me it worked but "the Carburator has a dripping leak see here ". "The o ring is a flat one we don't have here, but if you drive to this carb shop on Peck Road in Irwindale you might buy one to stop the leak". He didn't have the part so he returned the generator to me with a fuel dripping Carburator and $680 short of money with a fuel tank I was to repair or replace MYSELF and a Carburator I needed to fix myself!! Now I am really irritated to learn the fuel pump he quoted and installed retailed for $83-97, but I was charged nearly 300% of HIS cost. So basically I was charged $200/hr for labor and 3x the cost of a part and I still have to finish fixing the generator MYSELF. The engine does run which is why this review is two instead of ONE star. Not only this I asked about "another generator I have that needed fixing" and I was not asked to interrupt him working as he cut me off sharply verbally. Then I asked his nearby office lady Laura for information about my other job, and he told me "not to bother her, she has work to do". Well I guess my next job was not important enough to respect the only customer n front of them in order to earn it. Garry you need customer service lessons. You are lucky you are good at what you do mechanically, but you would never work for me. Now it's time to spend another wasted day finishing the Job my $680.00 tuneup at Advanced generator didn't accomplish. read more

I got cometely screwed here. I dropped off a Honda 3500 Watt generator. I rely on my generator every day for work so I dropped it off just before I was headed out of town on a 8 day vacation. I stressed that they only had 8 days to work on it and I needed it!. The guys name was Patton. Explained to him what my generator is doing and he says I need a carburetor rebuild for $180. He also said it'd be a good idea to give it a tune-up which included spark plugs, air filter, and oil change. This brought the bill to about $240. I return from my vacation and headed over to pick up the generator. It was not ready. It looked like they didn't even touch it. I was told they needed it for another 3 days!! I had to rent a generator for 3 days. When I got the phone call that my generator was ready I swung by to pick it up to find one of the wheels off the wheel kit. The guy who brought it out to me, not Patton, was dragging the frame across the parking lot. I paid and took the generator home. When I got home I looked over everything and it looks like nothing was done. I fired it up and it had the same exact problem I had when I dropped it off. Fuel would come pouring out of the carburetor. I call them back, this time Patton answered. I explained the situation, he said that if what they did didn't work then I will need a new carburetor that will cost an additional $150. I called Marunaka lawn mower shop in Covina and explained my situation. The gentleman there said that it sounded like I needed a carburetor. He also said it'd be a good idea if I did a tune-up. It's all the same thing I heard from Patton except the lawn mower shop quote me a price of $75!!! This wasn't a carb rebuild.... this included installing a brand new OEM Honda carburetor and tune-up for $75!!! Stay away from Advanced. read more

I we took our generator there weeks ago, maybe a month or more. We cannot get ahold of anyone at this business to try to find out the status of our generator or at the very least pick it up. Not sure if they are closed due to covid... we have tried calling numerous times and even drive by but they were closed. If anyone has information that could help us it would be greatly appreciated. I hate to leave a one star review and I'm happy to change it once we figure out what's going on. read more

Found this place via random search. Lucky for me, they had an opening the next day. They explained, over the phone, about the cost for the diagnosis. A while after dropping it off, Gary called to explain what he found, what the cost would be, and when it would be complete. He finished up almost exactly when he predicted and went over the repairs with me as well as suggestions on how to keep the generator running reliably. I would definitely go back for future issues. read more

Thanks a ton Gary for ALLLLL of your help and thorough explanation. I totally trust you and your Knowledge and Experience! If your estimate is high...it's not his fault! Your generation is simply in bad shape! Best wishes! read more

Overall I'm not very happy. They did fit the problem but it was a long process. I made an appointment to have my generator repaired with this company. They told me it would be fixed in one day, it took two weeks. I dropped it off they gave me a list of problems and said the repair would be $700 and finished later that day. I okayed the repair. The problem still existed after the repair. They called me back and said it needs another $400 in parts, I asked them if they were sure that would fix the problem they said yes. It did not! They then charge me another $500 and finally fixed it. These guys throw parts at it and hope it's fixed. Get ready to be overcharged under satisfied. read more

Advanced Generator Service really came through for us in our hour of need. We were traveling into the desert just when our generator died. They got us in and fixed up the day after the Fourth of July holiday. Great service! Thank you!! read more

I thought I could diagnose the problem with my generator on my own. But I ended up making the problem worse. After doing some research I found Gary at Advanced Generator. Gary found and fixed the issue for me and I couldn't be happier. I have now found my new mechanic for any generator service/issues. Thank you Gary!! If you need anything done take it to Gary, he cares about what he does and will fix your problems. read more

Hard to find a good RV generator repairman anymore. Gary was a pleasant surprise. Advised me on some repairs and his prices are great compared to dealer quotes. Glad I found him. Thanks again Gary! read more

I have been going here for years they they I'll was do a great job very experienced and knowledgeable ,, and get it done pretty Quick Gary is very fair and honest . We will have our generator service and it is good to for The Glamis session . !!!! read more

I called Gary on Thursday and told him I had an issue with my generator an Onan 7000 and told him I was going camping the following Friday. He told me to bring it in on Tuesday at 1pm. Came to find out he was in Palm Springs and came back to work on my generator. He is a straight to the point business man. He told me over the phone about the diagnostic fee and again when I arrived. About an 1.5hrs later he called and told me what the problem was and the price to have the motherboard replaced and asked what I wanted to do. By 4:15pm he was done. If you have a problem with your generator I highly recommend Advanced Generator Service great knowledge and service. Gary answered some questions I had about my Onan 7000 and even checked out my microwave when I told him I was having an issue with it. Thank you Gary, the kids are enjoying camping at the beach this weekend because of you. read more

On January 14th I called Cummins to get a referral to fix my generator that is installed in my 2015 Eclipse Attitude Toy Hauler. I was referred to Advance Generator Services in Azusa after calling other RV dealers that said it was a two week wait to get my trailer looked at. I called them on January 14th and they said I could take it in the next day and the cost would be $140 to diagnose the problem and if I did the services through them the $140 would go towards the cost of getting it fixed. We then set up a time to take my trailer in on the 15th and I told them I would bring it right when they open as I was hoping to pick it up before traffic started later that same day and Laura said we will see what we find. I took my trailer in and dropped it off. They called me at approximately 2pm or so to tell me they couldn't figure out the problem and I needed to pick my trailer up because they can't have trailers there overnight. I picked up my trailer. I called on the 16th and still no answer but Laura told me I would have an answer by Thursday the 17th. I called on Thursday and a Gary told me Laura was out sick and that it didn't sound like Laura to give me a day I should have an answer for my generator to be diagnosed. I thought that was odd as he was basically telling me I was lying. He then told me he wouldn't have an answer until the following Monday. Monday and Tuesday came and went and no phone call. I took it here because they make it seem like they were going to look at it right away but really they just take it out of your trailer so they have you locked in. At this point the only time someone called me was to tell me to pick up my trailer. I called on Wednesday the 23rd and Gary said he would have an answer that day but he never called again so I called back on Thursday and he said he knew what the problem was. He told me it would be $943.76 to change the brushes as they were worn, change the oil, change the spark plug and air filter. Wait What!!!!!! That's what I was thinking in my head. I told him I never asked for a tune up. How much without it? He said it would be $765.91. I couldn't believe he was going to charge that much to change oil, spark plug and air filter which takes me about 30 minutes. At this point I knew I didn't want him working on my generator so I said I'll just bring my trailer back and you can put it back in and I'll pay you the $140 for diagnosing the problem. He then said well now you have to pay $360 because he had to take the unit out. I said you never told me there would be a fee for this. He said that's just the way it is. I told him I would not accept that and would get others involved but I'm not paying more than $140 which was agreed upon. He started to argue with me but I was worried because he had my generator so I defused the situation. I didn't want to have to take it somewhere else but I couldn't trust him at this point. After hanging up I started wondering how he could even explain how it could cost that much so I called him back and said give me a breakdown how you came up with that price and after fumbling his words and putting me on hold a couple of times to figure out how to make it all make sense this is what he said: Brushes are worn out $140 for trouble shooting $145.91 for parts $220 for Remove and Replace generator $260 for brushes and removing plastic, Surfacing the armature and brush block assembly. $177.85 for Tune up service Total $943.76. He said if I didn't want the tune up it would be $765.91. I told him what about how you said the $140 would go towards the repair and he said that is not true. I couldn't believe these people. He said how much do you want to pay? I told him I would pay $500 just to get this done with and he came back and said $600 was the lowest which would include a tuneup that I didn't ask for but I had to give him a good review because he knew at this point he was getting a bad review. I couldn't believe what I was hearing. He has 15 reviews and 5 are horrible now 6 and explain what I am going through. That's 33% of his reviews are bad. I then called Cummins who originally referred me to him and someone there tried to resolve the matter. The Rep there said he would speak with a tech from Cummins who later said it should be one hour diagnose fee and 3 hours for labor and $105 for parts as that would be a warranty order if my generator was under warranty. That means I should have been quoted $545 minus the $140 diagnose which comes out to $405. I can't believe he tried to get double the amount. Who knows what the real problem was as the generator started no problem but you had to hold the start button to keep it running. I have lost sleep over thinking about this crook. I was not able to go camping and riding with my boys. This company should not be on Cummins service list. Please do not make the same mistake I did. If you have the same problem report him to Cummins so they eventually eliminate him as a vendor. read more

I had my motorhome generator serviced here last week. Excellent, honest work, at a good price. If you need Onan service don't go anywhere else. read more

My generator was runny poorly and I contacted Adv. Generator Service for assistance. I have worked with the owner before and he is very professional and a good diagnostician. I live several hours away but will only take my generator issues to him. He has always been right on the mark. read more

I got a tune-up for my trailer's generator. Service was very thorough and they gave me good info on how to properly run my generator. I will be here again for general upkeep. read more

Bought a brand new trailer and the generator wasn't working properly. The manufacture recommended we take it to Advanced. Once I arrived Laura looked at it and within a few minutes knew what the problem was. The generator had not been installed properly so it wasn't letting the exhaust out which caused it to over heat and would shut it down. The owner Glen called me and said he could fix it in about two hours. When i went to pick up the trailer they were just completing the work. Glen took the time to walk me through what he had done along with some suggestions on other parts of the coach. Very very nice people and very professional. I plan to have him do all the maintenance and up keep in the future. read more

After a larger RV dealer didn't feel confident in trouble shooting the generator in our toy hauler, I found this local facility. I spoke to Laura initially who welcomed us to bring our rig in the next day. Met Gary who is very pleasant to deal with. He seemed very knowledgeable and dove in right away. He made a few suggestions initially as to what the problems may be and investigated further. He did find a few other concerns and called me to discuss. After authorizing the additional recommended work he finished up the same day. One thing to know up front: They do not have storage/parking to leave a rig overnight. Be prepare to pick up the same day or bring back for completion. He removed the generator for the additional work required and installed the unit the same day I brought our rig back for completion. Not a big deal since they made me aware at the time I dropped it off. A+ to everyone there. Nala their shop dog is great too! Gary had all my old/ replaced parts for inspection as well. I know where to go if I have issues again. Thank you Gary and Laura. See you in the desert. read more

I really wanted to like this place. I was recommended by one of the owners good friends, granddaughter.. who he did work on her rv as well. I was also recommended by my godfather who services him and is his client. Never in my life have I had worse customer service. I just bought this RV, the owner knew that so I don't know too much. He told me he can't work on my rv because I need to dump the tanks. That is absolutely fine but the way he said it was "turn around I'm not working on your RV" and then walked away. He could have said hey sorry I'm going to need you to dump your tanks for this reason and then given an example. I had just driven 30 mins there and 30 mins home for nothing. His wife tried coming out to talk to me and I said "hey it's fine I'm just not going to give you my business" and all she did was put her hands up. Rude. Being a business owner, you should know how to communicate those things ahead of time and be polite. I will not be back and I'm definitely letting the people who recommended me know to never recommend this place again. read more

Great service. Another shop quoted a huge price to fix our generator. Said the carburetor needed replaced at a huge price. Brought it to Advanced Generator. Fixed it same day at half the price. Nothing wrong with the carburetor! We will definitely be a return customer and will recommend their services to our friends! read more