Dometic Fridge only works on LP

[RottweilerExpress]

So everyone here has been really helpful in the past. Figured i would shoot this by you guys/gals. So a few of you might know i just bought a 2011 cougar 31sqb. I went thru all my propane pretty quickly. So much so that i thought i had a leak. I mean i still might but it turns out my fridge was stuck on LP even tho im hooked up to shore power. I went thru the whole diag and thought i had it narrowed down to a bad control board on the back of the fridge. Just installed a brand new one with no luck same as before. Turn it on to auto and it just tries to fire on LP every time. Could it be the control board on top of the fridge inside that have the buttons?

Its a Dometic fridge. Im not sure on exact model i can get that. I verified i have 120v going in to the board (black wire). The receptacle is good. Even plugged into a outlet from my home same thing. I have 120v across the fuse. Fuse is good. Then i pretty much loose it after that. No voltage hits the the element wire/pin at all. Not that it matters in this instance but the element ohmed out at 40ohms. I thought for sure the relay soldered to the board was bad but like i said earlier. Brand new from a know working fridge did not fix it. Could it be the control board up top just skipping the whole a/c part on me? Seems like no matter what i do i cant get 120v to the element wire. Thanks so much in advance!!
-Ryan

[bigrockk]

Originally Posted by RottweilerExpress

I have 120v across the fuse. Fuse is good.
-Ryan

Not sure exactly which fuse you are referring too but just a heads up: If you are checking a fuse in a live circuit then 0volts across the fuse means the fuse is good, if you are getting 120volts across the fuse, then the fuse is bad.

Hope this helps!

[RottweilerExpress]

Originally Posted by bigrockk

Not sure exactly which fuse you are referring too but just a heads up: If you are checking a fuse in a live circuit then 0volts across the fuse means the fuse is good, if you are getting 120volts across the fuse, then the fuse is bad.

Hope this helps!

I appreciate the quick response! Not sure if i worded it correctly. Theres a 3amp and a 5amp fuse on the back of the fridge. One is for the ac side and the other is for the dc side. Im ase certified in dc electric and not too sure how 120v across the fuse is no good....anyway theres no voltage “drop” across the fuse. New circuit board came loaded up with new fuses anyway.

[FlyingAroundRV]

Ryan:
Check the continuity of the thermal fuse on the heater stack.
There should be a little round thingy on the side of the chimney stack. That's an overtemp cutoff. I think it uses 12 volts, but best to disconnect it and check with power off.
EDIT
Another possibility is what happened to my fridge when it did that.
My fridge had all the required voltages, but would only work on LPG. I eventually discovered that the connection to the fridge outlet was poorly wired at the breaker panel and not capable pf supplying enough current for the heater element.
Long story, short, when the fridge tried to energize the electric element, the voltage at that outlet would drop such that the controller board would switch over to LPG. Then the voltage would rise and the controller board would try to switch to electric. It was like a child playing with the light switch and it eventually burnt out the electric element.

[chuckster57]

If you have 120VAC at the board from the cord, but no voltage at the element pins then I would suspect the eyebrow board.

[ChuckS]

From what I could tell looks like the Dometic 2652 fridge.. but not certain since you never stated model #

I would get the service manual and go from there ..

https://fourwheelcampers.com/NewDome...atorManual.pdf

[bigrockk]

Originally Posted by RottweilerExpress

I appreciate the quick response! Not sure if i worded it correctly. Theres a 3amp and a 5amp fuse on the back of the fridge. One is for the ac side and the other is for the dc side. Im ase certified in dc electric and not too sure how 120v across the fuse is no good....anyway theres no voltage “drop” across the fuse. New circuit board came loaded up with new fuses anyway.

It might just be a matter of wording, when someone says they checked voltage " across" a fuse, to me that means they placed voltmeter leads on either side of the fuse in a live circuit. Weather it be A/C or D/C if circuit voltage is present and measured across the fuse then the fuse is "open" or bad. If zero volts (or extremely close to zero) is measured then the fuse is good and completing the circuit.

[RottweilerExpress]

Thanks so much for the info! Funny you mention the control board not being able to handle the ac volts. Ive recently been sorting out a “messy” wired up ac breaker box. According to my electrician friend that is.

Thanks so much for that service manual too! Past few days have been crazy but im going to do some more testing today!

[RottweilerExpress]

I deff didnt word that right! Been some time since i messed with my voltmeter and my terminology is always bad!

[RottweilerExpress]

Originally Posted by chuckster57

If you have 120VAC at the board from the cord, but no voltage at the element pins then I would suspect the eyebrow board.

Thats what im thinking as well. For 40$ i think im going to take a shot on it. Thanks again