First off, I did plenty of searching and went through about 12 pages of results with no solution.

Problem: My heater stopped heating.

I checked the cable for the hot/cold air selectrer ****, it is working, the cable moves a valve the driver side of the car. I looked while i turned the ****, it is working. I am not leaking water anywhere. Only thing I can think of is the heater core is clogged? Could that be a possibility or is there something else it could be?

BTW: 1985 GSL

 

If i'm not mistaken, there should be a sensor that opens up the passage to heating once the engine is warm. Where it is exactly though i don't know. You might just need to change that.

 

Right either a sensor or another cable.

There is two things that control the heat. The heater control valve which controls the flow of the coolant through the heater core (more flow = more heat). Second is the which path the air takes through the ducting.

Not sure about the FB but on the SA's there is another lever for heat, that controls a flapper. The flaps in the venting ducts direct the air from the blower to the heater core.

It could be either a bad sensor if it is electronically controlled or a broken/disconnected cable.

 

There is one vavle that allows coolant flow though the heater core, that's the heat dial/lever. The other control directs the heat where you want it. If either of those are not functioning properly, you won't get the heat needed.

Three other things can cause a lack of heat. The under dash ductwork is disconnected, the fresh outside air supply is not closing off, or the heater core is plugged. Keep in mind the heater core is a mini radiator. If your radiator is corroded and full of crap, expect the same for the heater core.

 

Let me clearify a bit more to help, sorry I didn't earlier.

I have electric controlls, not the manual ones. I can hear all the motors working fine when i push the buttons to change the "mode" or "direction" of air. All duct work is together and fine, I looked at it all when I ripped out my dash to paint my interior/change carpet. It was just working last week, and then stopped one morning. I've checked the manual, and I am thinkin I have to check the "water valve". I looked at the wire diagram and havent found it. I came to that conclusion by following the troubleshooting guide. I already know that my thermostat is good, and my radiator is not corroded, so the "water valve" seems like the next logical step, well that and the motor that lets the air go through the heater core or bypass the core. I dont know what that is called but looking at the diagrams, I think it could be that, becasue the car blows cold air if HEAT is pushed in and the dial is turned all the way clockwise to the RED. Got me so detective work to do tonight.

 

The water valve is what opens/closes the coolant flow to the core. It will be on one of the 2 copper lines just inside of the firewall. Lack of heat can be from that valve failing to operate or one of the doors inside the ducting is not working.