Dometic RM3663 Fridge

[biggjb]

My truck camper has the Dometic rm3663 fridge. Last year there was a short in light switch within the fridge when the door is open. I could not find a replacement so I just kept the switch taped down. No light but no further short either. Now I cannot even turn the main power on without the circuit breaker going off. I have tried to turn it on and then switch from AC to DC but nothing works. I cannot switch to LP either. When I do turn on the power there is a funny noise near the bottom back of the fridge. I have downloaded the wiring diagram and service manual but am not sure where to start. I understand the main power should be DC but could it be anything else.

[AnEv942]

biggjb wrote:
Thanks Old-Biscuit,

I disconnect the wires for J2 and the fridge works, however, the 20A fuse on the DC circuit board still lights up. Both the AC power is good at J5 and J6 are good and the proper DC voltage 13V is at J4. I did notice that the previous owner removed the DC heater element as there is nothing connected to J1. Does anyone know where I can get a replacement 12v heater element?

As to the 12 heater will be tough to find- its not being hooked up would have no effect on fridge working (or not) on gas or AC. IF its still there you can test ohms to see if good.

The indicator on fuse panel lit up, on P/D replacement converter fuse board- fuse pilots should only come on if fuse blown or removed?
I looked at older thread that shows your converter. Noted 20 amp fuse, mine is 30 amp for fridge but I also noted its on fuse slot #1. I doubt have any effect on issues but on our P/D converter the first 2 fuse slots are intended for low voltage use? I didn't use the 1st 2 fuse slots and wiring/fuses all is shifted over.

[NRALIFR]

A couple of years ago when I thought I needed a new DC heating element for my RM3663, I found that they were out of production and unavailable. IIRC it’s a 215 watt element, and I found a parts dealer that had an element they claimed was a suitable substitute for it. I bought it, noted that it was about 25 watts “hotter” than the OEM, and installed it.

Ran it overnight to make sure it was good, and it appeared to be working ok. When I got up in the morning, the fridge was warm, and when checking the DC fuse I found that the fuse was good, but the fuse connectors soldered to the Dinosaur control board had gotten hot enough to blacken the board around them. I returned the new element for a refund.

:):)

[enblethen]

I would not be using 12 volt element as it will eat battery. So I would not be installing new element.
If you want to, try ebay.

[biggjb]

Thanks Old-Biscuit,

I disconnect the wires for J2 and the fridge works, however, the 20A fuse on the DC circuit board still lights up. Both the AC power is good at J5 and J6 are good and the proper DC voltage 13V is at J4. I did notice that the previous owner removed the DC heater element as there is nothing connected to J1. Does anyone know where I can get a replacement 12v heater element?

[Old-Biscuit]

DC Breaker..........that sure makes a difference in diagnosis

AC breaker vs DC breaker
TWO totally different electrical systems

You need to start with that bad interior light ---DC Circuit

Re-Read 'AnEv942' post from yesterday

J2 is DC+ for the 'heater cable' the 'Light' and the 'Low Ambient Temp'

[enblethen]

What DC circuit breaker?

[biggjb]

thanks for all the tips. I unplugged the 120v then turned the power back on and DC breaker tripped. I then turned it off and also turned of the climate control switch as well. Turned it back on and the shorting sound stopped and the control lights came back on but the DC control light flickered. After Christmas I will take the cover off the lower circuit board and start testing the fuses and the others suggested.

My trouble all started with that interior light.

[Old-Biscuit]

AC Circuit breaker for fridge is tripping when you turn Fridge ON????

DC is for the fridge controls. display and functions

AC is ONLY for the AC Heater Element


SO it sounds like you have TWO issue
One with the AC Power from CB to Circuit Board (Outlet. fridge power cord, j5/j6 terminals on circuit board

One with DC Power on the circuit board.....which controls all functions

[AnEv942]

I would start by unplugging the light power wire at control board, J2.
Puzzling that it would short only when light on because the power wire to it is always hot? switch closed only grounds the bulb...
Not the problem though may have caused it (or still). As far as house power unplug the fridge verify 110 wiring/receptacle good.

Then its testing..manual http://bryantrv.com/docs2/docs/servtips.pdf
has some limited testing you can do.

[enblethen]

Yes, It could be failed circuit board 120 volt relay.
Unplug refer in the outside access. Problem should go away. Then inspect circuit board.
If circuit board is bad, replace with Dinosaur Electronics version.