Dometic Americana Temperature Control Failure

Snip-the-tip is easiest, works well AND gives you a mini adjustment controller.

Otherwise you have to try and pull new thermistor wiring thru fridge liner and insulation down to control module without damaging the wire.

Control module is accessed via outside lower vent........thermistor plugs into P2 connection on board.

Old-Biscuit wrote:
Snip-the-tip is easiest, works well AND gives you a mini adjustment controller.

Otherwise you have to try and pull new thermistor wiring thru fridge liner and insulation down to control module without damaging the wire.

Control module is accessed via outside lower vent........thermistor plugs into P2 connection on board.

Thanks Old Biscuit. I thought the board might be accessed from the outside.

I guess the first thing I should do is check the board end to make sure it's even plugged in.

Do local mom/pop RV stores have the snip product or is that just an online purchase? I'll find out soon enough once the stores are open again.

Only seen it for sale on-line

Doubt if it is NOT plugged in....connector has a catch on it that has to be released to pull off board.

The 'bulb' end should just stick out of clip and clip should be attached to right hand fin n food section.
If it has fallen down it will cause fridge to over-cool.

Are you POSITIVE the thermistor inside the refer is attached to the fins and not hanging loose? If it hangs loose the refer will freeze. Doug

I think I'll check mine. It doesn't freeze the fridge, but even w/ the temp on 1, it seems to burn way too much, and everything in the freezer is brick hard,
I always turn it off at nite, but even that doesn't change much w/ cooling.

The connector may be latched in place but there could be a little corrosion in the two-wire connections themselves. I helped with a Dometic that was freezing everything. Tested Thermistor and it read out OK. Plugged it back in and left, thinking I had NOT found the bad Thermistor problem I'd suspected. Next day she's thanking me for fixing it. I think I reduced resistance into the range where the thermistor could tell the cooling unit to stop.

EDIT to complete this reply...

In a Dometic manual, I found the resistance of a thermistor should be 8,000 to 10,000 Ohms at 32 to 36 Degrees F. Proceed as follows:
1. Prepare an Ice Water Bath. Cup of mostly Crushed Ice, partly Water and Stir. This gives you the 32-36*F.
2. Unclip Thermistor from Fin and Submerge in the Ice Water Bath. Swizzle for a few seconds and let stand a couple minutes.
3. Disconnect Thermistor Plug from Control Board.
4. Measure Resistance across the two pins of the Thermistor Plug. DO NOT probe up into the cavities that slip over the Pins on the Board. Rather, touch the probes to the exposed contacts at the opposite end, the ones you can see before unplugging the Plug.
5. Meter should read 8-10,000 Ohms.

Nothing wrong with Snip-the-Tip as a replacement part BUT do this test as well. If you just assume it's Thermistor and change it without working the contacts at the board, you could still have excess resistance in the circuit. Even if the Thermistor was actually Bad.

dougrainer wrote:
Are you POSITIVE the thermistor inside the refer is attached to the fins and not hanging loose? If it hangs loose the refer will freeze. Doug

Clip IS attached to fin at right side of fridge.

Will look to see where tip of thermistor is relative to clip.

Will attempt resistance ice batch test this weekend (too dark to check after work, parked on street, don't want to get run over searching for controller board).

Does sliding the clip up or down on the fin affect the temperature at all?

LaunchnRetrieve wrote:


Does sliding the clip up or down on the fin affect the temperature at all?

Yes. Sliding it up makes the refrigerator colder (you located the sensor in a warmer area of the refrigerator-- heat rises).

Sliding it down warms the refrigerator by locating the sensor in a cooler part of the refrigerator.

Changing clip/thermistor position on fin can have a minor temp affect (4*-6*F) IF your fridge does NOT have an adjustable temp control on upper panel.
If you can change temp set point on upper panel than clip/thermistor should be mid position right hand fin.


IF you do NOT have an adjustable temp setting on upper panel then sliding clip UP will cause 'cooler' temp in food section.
Sliding it DOWN will cause 'less cooler' temp in food section
Usually there is an indication on liner wall IF moving thermistor will affect temp



Even when a thermistor passes resistance test..........doesn't always mean they are properly functioning

BAD Thermisters can OHM correctly. The Thermister is NOT sensing the air temp but the evap fin temp. The air temp will be 10 degrees warmer than the fin temp. If your refer is at 36 degrees the fin temp will be 26 degrees and that 26 is what the Thermister is responding too. Doug