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drhotwing1 · 06-18-2020, 01:55 PM

Hey there, I'm having an issue with my RV fridge. I'll provide as much detail as I can here but need some help.
I have a 1985 Fleetwood Jamboree RV with Dometic RM763. I can't get the fridge to run on anything except for LP. On LP the pilot lights and the fridge cools and works pretty well for an older fridge. I have been troubleshooting as much as I can and I have and user/troubleshooting manual but the pictures are too dark to see anything.

On my Chevy dash console I have a refer control toggle switch labeled 110v/LP and 3-way. I have tried both. When on 3-way I start the fridge and the LP mode starts and pilot lights, then I started the RV engine assuming that the LP mode would switch over to 12v mode and the pilot go out but it stayed on. I then turned the motor off and plugged in the shore power (110v) and the LP pilot stays on. When I close the LP valves hoping that 110v would kick in but all I hear is the clicking of the spark trying to run the LP. So i'm getting only LP mode running no matter what I try.

On my model I can't find the fuse for the 12v but I would assume that if 12v fuse was bad LP wouldn't work either.

I also can't seem to find the circuit board that everyone talks about. I don't have a plastic box on the left of the outside unit. I do see the 12v connection terminals (ignition/+/-), and noticed the green wire for the ignition goes to the console. When looking at the refer control I noticed a green wire just hanging there not connected but I don't know where it goes since I can't find a diagram or picture of the switch anywhere. I assume that the hanging green wire is from the ignition terminal on the fridge and it connects to that switch but I didn't want to plug it in until I know for sure it goes there.

As for further testing, I will be testing with a meter later on today (110v outlet, 12v terminal etc) but I don't see where the relay or circuit board is.

Can someone point me in the right direction. I'm maniacally inclined but I never worked on a fridge before

Here are some photos;

https://flic.kr/p/2jcq422

https://flic.kr/p/2jcq3eF

avfordguy · 06-18-2020, 11:18 PM

From what I remember a 3 way fridge ONLY works on 12volt ( heater element)with the chassis engine running ,most of them that i have had the 12v heater element was toast. Parts may become hard to get for that vintage. I would be more concerned about 110v and propane.

avfordguy · 06-18-2020, 11:24 PM

Google your dometic model, I found the trouble shooting manual!

drhotwing1 · 06-19-2020, 10:06 AM

Thanks. My model has 2 heating elements in it, 1 for 12v DC and one for 120v AC.
With the chassis running from what I understand the LP is supposed to turn off and the 12v heater is supposed to take over but LP won't shut off.

I'm wondering if the problem is the relay but I can't find it

avfordguy · 06-19-2020, 03:56 PM

This is about as good as it gets !!
Sure hope this helps!Dometic-Service-AES.pdf

avfordguy · 06-19-2020, 03:58 PM

Seems I cant upload a .pdf what gives??

avfordguy · 06-19-2020, 04:00 PM

Manual for fridgeDometic-Service-AES.pdf

drhotwing1 · 06-19-2020, 07:53 PM

I have both of those manuals and have read the troubleshooting. One of my big issues is that there is a switch right under the steering wheel in the chassis. I can't find anything anywhere about this switch. There is a green wire that I believe is the wire connected to the ignition lock terminal, that is just handing there next to that switch. I need someone to verify if that green wire plugs into the back of that switch or not.

Also, the troubleshooting steps say that there are 2 screws on the left and one near the burner that need to be taken out to access the circuit board and relay, etc. I can't see the picture of where where screws are exactly.

Thanks,
Jeff

drhotwing1 · 06-22-2020, 03:17 PM

OK so I figured out how to get to the printed circuit board on the rm 763 to find the 2 fuses on the board were burned out. I replaced them with slow blow 3a fuses and bingo the fridge is working again.

My only question now is this; in the manual it says to use a 3A glass fuse but on the circuit board it says use 5A only. Which one should I be using?