tkbowers

Kay, The ATS relay drop has happened only once since I had my generator repaired almost a year ago. Prior to this repair, I was having a similar problem, but with much more frequency. However, when the generator ran properly, voltages hovered around 120 VAC. This low voltage condition was a known issue with my particular model, and was caused by operating it in high humidity conditions. I attached a copy of the Onan support bulletin for reference. The repair was successful, but I noticed that normal voltages were now in the range of 110 to 112 VAC. I was told not to worry about it and anything above 108 VAC was acceptable. You've given me a lot of good information. I use my motorhome every month, will observe and keep an eye on things, and perhaps update this thread. Thanks again. Tom Onan Product Support Bulletin 637.pdf

Thank you for your reply!

Kay, Now I understand, measure voltage upstream of the ATS. I'll be dry camping at Quartzite next month and will have many opportunities to do this. Thank you!

Thank you for the information on my ATS. My generator runs at 1,800 rpm. Please explain your statement "...,also insure the ATS is not in line for testing."

I will be traveling from Northern California to Quartzite, Arizona next month. Are there sources there for filling potable water tanks? I prefer to travel with less than a full tank just to keep my weight down. Tom 1994 Foretravel U-240

I'm responding to posts from a number of individuals. Yes, I used a hand-held digital voltmeter. If the voltage is electronically controlled, I assume that means that it is not adjustable. The generator engine appears to run fine. New brushes were installed this past February, but no mention on the invoice of polishing the commutator. How do you polish this component?

I have an Onan Marquis 6500LP generator, Model 6.5NHMFA26115C, S/N A953989409 (electronic ignition) in my motorhome with just under 1,000 logged hours. What is involved in bumping up the output voltage? While dry camping this month, I was charging my batteries, and the automatic transfer switch dropped out for about a minute not long after starting the generator. It re-engaged on its own at which time charging appeared to proceed normally. The output voltage on my generator generally runs a bit low (110 to 112 VAC), and I'm thinking that a momentary dip below this output may have caused the interruption. I replaced the transfer switch (Esco ES50M-65N) in June of 2014 and assume that this equipment is still functioning properly. Thank you. Tom 1994 Foretravel U-240

I would like to update everyone on my refrigerator issue. Last week I ordered a replacement power module ($229) and installed it yesterday. I started the refrigerator and let it run overnight. It was still running when I checked it this morning, so I think my problem is solved. Thanks again for your help! Tom 1994 Foretravel U-240

Thanks everyone! The cable checked out okay using my ohmmeter. I'll keep you posted.

Dometic claims that they do not have a tech support group and referred me to my local service centers. If one is to believe the error code, the problem should be either the display, the power module, or the cable connecting them. I tested the cable and all three conductors checked out okay.

My Dometic refrigerator, model RM3762RBX purchased August 2011, stopped working. I woke up this morning to error code EO (No communication between display and power module). I have verified adequate voltage at the unit, plus ground connections and fuses appear to be good. Three conductors (brown, black and red) connect the display and the power module. My next step is to test resistance of these conductors. If that checks out okay, I'm planning on ordering a new power module ($200) and/or display ($120). I could just order the power module first and see if that corrects the problem. Something tells me that component is more likely to fail than the display. Suggestions? Does my thought process make sense? My local RV repair person charges $30 to show up and $100 per hour. I assume he marks up for parts too. Experience has taught me that costs escalate quickly whenever I hire "pros" to work on my motorhome. Thank you. Tom 1994 Foretravel U-240

Wanted to let you know that I ran a new conductor for my backup lights. I verified no more blown fuses when I put the transmission into reverse! Thanks everyone for your help. Tom

Thanks Herman. Brett is correct, I'm having an issue with the black wire. More tinkering today and will keep you posted.

Thanks Rocky. My wiring diagram shows no devices other than the back up lights.

LewEngle, I like your idea. However, wiring, tubing, and piping are bundled very tightly in a raceway running lengthwise in the basement. I'm reluctant to disturb these lines too much for fear of creating a problem in another circuit or system. My vehicle is 22 years old. I disconnected both tail light assembly plugs. To my disappointment, again the fuse blew when I put the transmission in reverse. This tells me that the short is downstream of the relay and upstream of the plugs. Brett mentioned that there is a wiring harness further upstream of the tail light plugs. I found this device on the wiring diagram and as a next step will attempt to locate it on my coach.