[A/S] Re: Temp Indicator Help

["nickcrowhurst" <NickandSandra@xxxxxxxxxxx>]

Good evening, George. I had a similar problem with my 1988 Excella. 
Minus 40 is the temperature displayed when the temperature sender 
unit becomes detached from the control panel, perhaps by a wire 
breaking. You need to find the sender unit. Try lying on your back 
under the right hand side chassis member where it disappears into 
the aluminium body, under the lounge area.(Wrap up warm, it IS minus 
40!!!) Where the side panel wraps round to meet the floor is an 
overlap between the panels, and my sender unit was pushed in there. 
It is a plastic board about one inch long by a half inch wide by  a 
sixteenth thick. This should have 3 wires soldered to it, perhaps 
brown, orange, and red. If you are lucky, you will find one of these 
wires broken at the soldered joint, perhaps by vibration on the 
road. Re-soldering the joint should do the trick, making sure to 
disconnect all electrics via the battery kill switch before doing 
so. These wires disappear into the trailer, and emerge at the back 
of the control panel, where they enter a printed circuit board. 
Calibration of the inside and outside thermometers is via two green 
potentiometers on the printed circuit board, marked IN and OUT. If 
the sensor is properly connected via unbroken wires, the voltages to 
earth at 55 degrees are brown 2.8v, orange 2.8v, red 9.7v. Beware, 
the potentiometers are extremely sensitive to the slightest touch. 
By the way, my internal sensor is tucked beneath the radio-cassette 
player above a small vent hole. If you have recently removed the 
control panel for some reason, you may have disturbed the circuitry, 
and the problem may be there if the wires are unbroken. I hope this 
helps. Good luck, from Nick C.