The little curveballs keep coming ... refrigerator thermostat "bypass"????

[Xbird]

Hi all, getting down to the nitty gritty last lit bits sorting out the Jamboree inside and out. I'm basically eliminating everything that was added to it over the years or trying to figure just what and how things that were added to it work -- if at all.
My latest on has been a puzzler since day one. Next to the pair of switches by the entry step (the pair controls the 12v house lights and the exterior amber light by the door top) I have a toggle switch that is definitely 1980s or newer. It's got sheathed 12v cable for a (ground/accessory/power) terminal setup. it pulls power from the neighboring switches. Chasing it out, it goes to the exterior access to the  duotherm refrigerator. behind the fridge the + is interrupted by another toggle switch that appears much older. there's an old paper tag on it with a hand drawn picture of the switch and "thermostat bypass" on it. the drawing is to reference the switch shape in order to turn it on or off in the right direction.

Following that toggle, the sheathed cable then goes up the side of the fridge and into the unknown. I've looked high and low for where it may go, it is not for the heater thermostat so the only assumption I can make is that it must go to the refrigerator. I have no way of checking the sides or start controls/thermostat on the fridge without tearing into the woodwork. The refrigerator has worked in the past on gas and shore power. I'm really clueless as to why one would send 12 volts at the thermostat in this manner with the option of turning it on and off in two places on the same wiring run.
Any insights would be appreciated.

[TerryH]

A bypass for the fridge thermostat makes no sense at all. It would either cause it to run continually or not at all.
Is it possibly for your furnace? Depending on where your furnace and furnace thermostat are located (mine are on opposite sides) the wiring 'could' run up, across the ceiling, and then down between the two. However, thermostat wiring is generally light gauge, drawing low amperage.

[tmsnyder]

Maybe it allows the fridge to run on DC even when the engine is not running?  Thus running your battery dead quickly, but hey, your beer will be cold for an extra 2 hours!

[Xbird]

had the same thought about the heater, (is on opposite side) but the wire does not show up there or at the T-stat for it, which is mounted on the opposite side wall of the fridge. Tag actually says "thermostat override" and "Auto" for the two switch positions.
 

[Xbird]

Man I wish we had an edit function! i was mulling over the 12v thought, but the fridge is plugged into an AC outlet in the outside access area and i see no provision at all for DC power into it in the that area.

[tmsnyder]

Maybe it was for an old propane / 12V fridge which is no longer there but the switch is.


What I've seen is a 12V signal coming from the ignition switch to the 12V refrigerator circuit as a low amperage signal, to let the fridge know that the engine is running and allowing the fridge to run on 12V.  The switch you found may be another way, installed by a PO, to run the fridge on 12V even when the engine isn't running. 


Just a theory.

[Xbird]

I know from the manual that they offered a 12V option for the fridge, but wouldn't a setup like that have some visible components in the heater section? the fridge itself looks to be the original.

[Xbird]

Well, a couple years down the road and I have my answer now that I tore walls off  Switch in this discussion. When I removed the refrigerator side wall after removing the counter housing the hot water heater, I was able to trace the cable up to a fan mounted behind the fridge just below the vent cap. Not really sure why it's set up this way, either fan didn't exist and PO found that the vent system needed some help, or it was done to vent it while driving with the fridge running on propane. 

[Elandan2]

The fan was installed to aid in the movement of air over the coils on the fridge. It helps the fridge cool better in extremely warm weather.

[Xbird]

makes sense. not sure if it even works, never heard it running. at the moment, i have everything electrical shut down until i'm done.