Auto Heater Question

[Red Devil]

OK, Everyone I talk to says that I am nuts and should just convert to manual heat but I just can't give up yet on my 1980 SC Targa. Whether I turn the switch to the 1, 2, 3, or even 9 position, the handle goes all the way to the top opening the flapper to let all the heat in. You will literally fry within a few minutes. If I turn the switch to the 2 or 3 position, shouldn't the lever only raise slightly and not all the way? Could this be the temp sensor in the heat exchanger or switch itself? Thanks....

[emcon5]

Mine did that too, IIRC the troubleshooting list for that symptom is the cabin temp sensor. The solution was to disassemble it, clean the connections and put it back together. Been working fine ever since for ~6 years.

Not sure where it is on a Targa, but on a coupe it is above the rear view mirror, a little rubber nipple thing hanging down between the sun visors.

Tom

[Red Devil]

I actually spent the couple hundred bucks on the new cabin sensor hoping that was it. So, when you turn the dial to lets say position 2, does the heater lever only slightly raise? And the higher the number on the dial determines how high the heater lever arm raises?

[fireant911]

I too am very curious about this behavior. My autoheat performs in the same fashion. Controlled heat would be a nice change instead of the two spectrums of either off or wide-open. I have been wondering about the same phenomenon that Red Devil is describing.

Subscribed.

[Mark McClure]

The inside thermostat is under the dash in the middle. It has a hose that runs from a small vent intio the thermostate. A small fan draws the air down the tube in order to sample the cabin air temperature.

I also did a bit of work on mine about 5 years ago....added the thermostat cleaned up the wiring and all is good...

Cheers

Mark....

[Peter Bull]

If the auto heater in the SC is anything like the one in the Carrera 3.2 you can try to adjust the resistance in the potentiometer which is connected to the twist switch. IIRC you remove the knob and behind it there's a small screw for adjusting the resistance. The procedure is quite well described in the Bentley Carrera 3.2 manual. You will need a decent multimeter to do the job.

/Peter

[Red Devil]

Thanks for the replies. This is actually turning into an obsession to fix. This is literally the last item that I need to get working properly and then every single light, instrument, and switch works as it should. I even went so far as to replace the tiny bulb that goes over the ashtray. My mechanic is still trying to convince me to go manual though, but he says it with a smile on his face like he knows it will only be a matter of time that it will go out once it starts working properly....