heat/defrost problems 86 TC

[gadget73]

First up, we have an annoying rear defrost issue. It works, but for some reason does not shut off with the ignition switch. It ran my battery dead last night. The light for it shuts off with the key, but it seems the power drain continues. When I opened the door, the lights were almost out. Flipping the switch down brought them up a bit, so I can tell it was drawing power. Any idea where I shoudl start looking for the problem? Is there a relay somewhere that could be stuck?

My other problem is with the heater. The heat itself works OK, the blower works in every position but 'floor'. There is a small bit of plumbing that the previous owner removed, but I do not know what its for. It looks like a plastic pipe, about 3" long with a temperature sensor in it. There is a plug with two electrical connections on the side, and two vacuum connectors. Does that part have something to do with the problem? I don't know where in the car it came from, because it was sitting on the floor when I got it. He told me that it leaked (it is cracked) and he removed it to stop the coolant leak. So far as I'm aware, the vacuum lines are plugged off, and the electrical connector is just dangling from the harness someplace. I'm planning on going junkyard shopping for some assorted parts next week, so if anyone knows where I should look to try and locate that part, please let me know. Thanks!

 

[Pepsi2185]

I believe the rear defroster is all self contained in the switch. I never got a chance to tear one apart, but the timer sounds like it clicks from the switch and ive never heard a relay. I would start there pulling the rear defroster switch, test for an ignition and possibly pull the defroster switch and replace.

As far as the floor vent, i have had the same problem in both my 88 and 89. Supposedly there is a heat sensor in the floor vent that measures when the temperature rises and actiates the blower fan. It is either electrical actuator or vacuum actuated. I believe it is toward the pass. side, but i will look into it further.

 

[gadget73]

I believe the rear defroster is all self contained in the switch. I never got a chance to tear one apart, but the timer sounds like it clicks from the switch and ive never heard a relay. I would start there pulling the rear defroster switch, test for an ignition and possibly pull the defroster switch and replace.

As far as the floor vent, i have had the same problem in both my 88 and 89. Supposedly there is a heat sensor in the floor vent that measures when the temperature rises and actiates the blower fan. It is either electrical actuator or vacuum actuated. I believe it is toward the pass. side, but i will look into it further.

OK, I'll just grab another defrost switch from the junkyard tomorrow. I'm just surprised that its fulltime hot instead of ignition switch controlled.
I found the heater thing too. Well, the plugs for it at least. Mine is vacuum/electric controlled. The sensor was originally located on the passenger side directly in the hoses to the heater core (the lower one I think). I just took the electrical connector and made a wire jumper for it. Blower works fine now. I have no idea where the vacuum lines are, as I did not disconnect them. My friend told me he plugged them off, but who knows. The heat works without kicking the AC compressor on, which is all I was really concerned with. The 180 stat really helps a lot with heat too. Perhaps if I see one of those parts on a car in the junkyard I'll grab it, but I don't think I'm really going to worry about it.

 

[Pepsi2185]

On mine the defroster is powered by an accy wire in the ign switch. So either your ignition is staying on or the switch is staying on. You have a test light?? What colors do you have in the switch??