heater problem
 

Hi Guys,

I have noticed that my heater stopped working. Whenever I move the lever to "echo" or "auto" and then move the temp lever - there is no affect. Only cold air.
I checked the heater valve and it does seem to close when I start the engine so no problem there. When I shutdown the engine it is opened and then I can feel the heat from the vents.

I read that the problem may be with the inside temp sensor. If it is faulty the heater will not turn on. There is also an outside temp sensor but I am not sure if I have it (its a 1980 model)...

My questions are:
1. Is there any fuse relay that I have to check?
2. How can I make sure that the inside temp sensor is ok? how can I test it?
3. Where is the outside temp sensor and how can I test it?
4. Is there anything else I should look at?

Thanks!

the outside temp sensor is under the left headlight,
the inside is on the console behind the small grill next to the vent outlet.

The WSM has diagrams and wire colors for the sensors,
remove the right side console cover and find the wire bundle to check the sensor strand.

I had this issue and it turned out to be 2 relays were bad,
one was the HVAC relay and the other may have been the blower relay,

I hope Alan will jump in here as he has the diagrams to cross ref the circuits

The blower works fine so no problem there. I will try to find the HVAC relay (didnt know that there is such relay)
In case it will be ok, how do I verify that the temp sensors are ok?

Can you please let me know the location of the HVAC relay? maybe I am missing something but it is not located along with all other fuses / relays.
In addition, how can I know if the temperature sensors (inside and outside) are good or faulty?

Thanks!

Look down the "posts" a bit, there was one showing this relay being replaced.