I was having a problem with the in-dash temperature gauge. It was stuck at about 38 degrees. I replaced the sensor with a new one from Winnebago and it still is approximately 20 degrees off (low.)

I called Winnebago and they didn’t have a clue as to what could be wrong.

The temperature sensor and the compass directional sensor are separate from one another. Is it possible that the compass sensor could be interfering with the temperature sensor and be causing the problem

Any input from those who know would be appreciated.

Not sure how those things work or are wired, but when electronic devices start acting squirelly and a direct replacement does not solve the problem a bad ground is a distinct possibility. Appears that you are picking up some resistance from somewhere in the circuit. I would start by running down all the wiring (if you can get to it) and checking for good tight conections while looking for rust at any of the connections. Hope this helps..

chief...
my dash temp gauge reads below the middle mark, i could not tell what the actual temperature was. only that it reads the same all the time when warmed up. it looked like about 170-180 on the dash gauge.
i installed a scangauge ll from mileage pros on line.
much to my surprise i found that the actual coolant temperature is 197-202 degrees and that is normal.
i have the 5sp ally and now have a digital readout of the trans temp as well as about 20 other parameters.
i can have 4 parameters reading at any time and change them at will.
i understand that at this time you cannot get a temp reading with the 6sp ally, but that they are working on it.
my ally runs at 137-142 deg with regular dexron lll atf. i am going to install amsoil tes295 synthetic fluid soon. it will be interesting to see if there is any difference in temperatures.

I don't see how the compass and temperature sensors could be interfering with each other. Your temp sensor operates by varying the resistance on two wires to the main display unit. The compass module should have no effect on that. You can unplug the compass head from the back of your display to eliminate it if you want. That'll verify that it is not affecting anything. My guess is a bad display unit. That's the part that actually converts the temp sensor's resistance readings into useable data, then display it on the fluorescent display.

I had one of these on my 2003 Suncruiser 333V and like it enough that I put them in my 2004 Allegro Bus as well as my '07 Bus. The manufacturer website is http://www.atcomp.com/php/protypecat.php?type_id=2&prod_cat=6 and you can download an installation manual for it from their site.