1991 Heater Not Working

Hillrun1 · 01-19-2005, 01:04 PM

Does anyone know where a relay may be to control the heater controls. The heater does not work and I have checked all of the fuses. The control cable is not moving when you switch the heater on. The valve moves freely but the box under the dash is not moving the cable.
Thanks

whtteg · 01-19-2005, 05:11 PM

So does the blower blow air out?
If it blows air out you are saying that it is cold and the the temperature control will not slide to the hot side, or that it is not moving?

Give a little more detail and we can probably help you out

Hillrun1 · 01-20-2005, 10:52 AM

Thanks for the help.

The blower works fine. It just blows cold air.

After checking all of the fuses, I disconnected the cable going to the valve in the engine compartment and it moves fine. The cable will not move.
I took out the glove box and found where it connects inside and the cable and lever will not move.
In reading the repair manual, it looks like there may be a heater relay switch but I sure can't follow the electrical diagram to find it.

Thanks again.

whtteg · 01-20-2005, 04:22 PM

I am 90% sure that all there is to the heater is a damper that is moved by the cable that allows the aire from the blower to be blown across the heater core. There should also be a small valve on a heater hose under the hood that has a cable conected to it as well. This is a valve that opens the flow of coolant to the heater core. If both of these are functioning correctly then I would proceed to possible remove the blower unit and make sure that the flaps are still connected inside the unit. If the flap is not connected any more than the air flowing by will keep it closed.
I will try to post up a picture for you, but at the moment my FTP program is not working so no uploading for me.

Hillrun1 · 01-21-2005, 05:33 PM

The valve under the hood is operating correctly when I undo the cable so it is not the valve.

When I took the glove box out, I can see a cable going to a box below the radio which appears to go to the engine compartment. The other box, near the passenger side wall also has a cable and that is not moving either. If I disconnect that, the flap opens.

I think there is a relay that controls these boxes but I am not sure which one is it since there are about 12 relays and they are not marked.

Thanks again.

whtteg · 01-21-2005, 05:35 PM

Oh ok you have buttons and not a lever to change settings?

POST REPLY TO THIS THREAD