It's Fixed!

[swebster]

To answer everyone's questions and describe what I think happened; the fridge was not working in any mode, 120, 12 or LP. No ammonia, no green particles on the condensor, etc. Just seemed like a dead fridge. Once I removed the board cover I could see that the 12V lead was toast (literally). I replaced the board and ran a new wire into the 12V block. I suspected that the 12V lead as wedged between the board case and cover which eventually cut the insulation and shorted the wire and board in the process. Everything upstream seems OK from a wiring perspective. I also found the thermostat wire disconnected from the relay (maybe a PO attempt at disabling the unit?). In any case, I reconnected and checked all wiring harnesses and connection, turned it on and this morning when we checked the fridge we had ice in the freezer!

Thank you James. Those troubleshooting guides are amazing! I appreciate everyone's advice on this. We were making due on this trip without the fridge but it sure is nice to have it back.

[ViewRVs]

I bought a thermometer that hangs from the wire shelf just to monitor the fridge temp. I re-assure myself each day by checking the temp. I get good temps on LP and 110 but I suspect my 12v is not working right.

Great to hear your back up and running. Before long, these Classic units will all be good as new!

[87MH]

Fred:

Don't know just how your's is hooked up -- each MH seems to be a little different, but on the 3800 in the 87 345 the 12 volt option is only operational when the motor home is under way. The 12 volt cooling on the fridge is hooked to the motor charging system, and only kicks in when the voltage is above 13.8 volts, i.e. only when the alternator is charging.

I assumed this hookup meant: propane when boondocking, 120 when parked with hookups, and the 12 volt cooling operational only when underway.

I see the 12 volt "only operational when the alternator is charging" as a safety/operations measure -- prevents the MH battery from being discharged by the operation of the 'fridge.

BTW, the 'fridge draws about 18 amps (on my unit), so it would not take long to drain a battery.

[swebster]

The Dometic manuals says it steps from 120V to 12V to propane, but I agree that this only seems to be true when underway in my 86. In any case the new board and reconnected thermo lead means I now have cold ones in the fridge! Yippee!

Still fighting the generator but I I've started pulling the carb off for a complete cleaning. Everything is pointing to gummed up needles so hopefully this will work out.

It sure would be nice to have roof air for the 1200 mile trip back home!

[thenewkid64]

The wire that was disconnected may have been done to attempt to place the unit in "limp mode". This will cause the unit to run non-stop in gas or electric mode hopefully keeping the contents cold.

This is a guess, but it may be what was done, or it could have been someone checked it, the board was toast and they failed to completly reasemble the unit.

[PeterH-350LE]

Originally posted by 87airstream345
..... The 12 volt cooling on the fridge is hooked to the motor charging system, and only kicks in when the voltage is above 13.8 volts, i.e. only when the alternator is charging.
.....

Dennis, glad to hear that they put some brains behind it in the later models.
My 12V refer function is wired to the coaches 12v system and I installed a warning light by the door, which tells me the refer is on 12V.
Also comes in handy in case of a blown fuse.

[thenewkid64]

Peter,

You could isolate it wih a ignition activated relay. The wire to the relay would not need to be large, and if the refer is automaic switch it will just try to lite on gas or switch to 120 Volt when you stop. I know, just another upgrade to add to the to do list. :d

[PeterH-350LE]

Originally posted by thenewkid64
Peter,

You could isolate it wih a ignition activated relay. The wire to the relay would not need to be large, and if the refer is automaic switch it will just try to lite on gas or switch to 120 Volt when you stop. I know, just another upgrade to add to the to do list. :d

Or run a fat fused wire to the A terminal of the Isolator.