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Discussion Starter #1
I have been reading up and seen where others have had no heat from their heater core. That is not my problem. My issue is the exact opposite. My heater never turns off. I have an '82 P-Type. I can turn off the fan but I can still feel heat lightly coming through the vents. It's too darn hot to drive in the summer. Any thoughts on what I can do to stop the heat? The control panel is kind of floating there. A previous owner broken whetever it was screwed to. Of course my air conditioner is non-operational.
 

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Typically that means you have a temperature sensor unplugged/not working properly. I believe if the one in the cabin under the center console is unplugged/not working properly then it will always blow hot. There is the outside sensor that should be attached to the condenser bracket in the front of the car. Can't remember what happens if that is not working properly.
Here is a link to the TSRM section. MK2 TSRM On-Line

To temporarily fix it you can unhook the vacuum lines at the water control valve that is by the wiper motor.
 

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Did the previous owner remove the AC and in particular the condenser. A lot of people when they do that remove the unplug and remove the entire condenser. On the condenser bracket is the external temp sensor. When you unplug that you get full heat all the time.
 

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Discussion Starter #4
Did the previous owner remove the AC and in particular the condenser. A lot of people when they do that remove the unplug and remove the entire condenser. On the condenser bracket is the external temp sensor. When you unplug that you get full heat all the time.
The AC system is still there. It just doesn't work. But I am gonna go check the temp sensor right now to make sure it is plugged in. Thanks.
 

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Yeah, we were just talking about this problem in this thread here...
 

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Discussion Starter #6
I checked the sensor at the condenser. Man do I regret that. Someone has cut one wire, going in, there is a red wire someone else had hooked up going to something else that I have no idea about. I am at a loss. I haven't really worked much with AC systems so this will definitely be a bit of a learning experience for me. Now I just need to know where the wires were all supposed to go. I wish I didn't need AC. I am going to try Darrow's trick of unhooking the vacuum line to see if that stops the heat. I'll take some pics of what I am working with.
 

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Discussion Starter #7 (Edited)
So the passenger side (right side) looks good at the condenser.
1.png


The driver's side, not so much. There is a wire cut from this plug in pic #2. I am not sure if this is just a plug or if it is the sensor. The other wire (red) goes from this plug to a black wire and then immediately back to another red wire in pic #3.
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So the wire from Pic #2 joins a wire from the compressor and into a wire harness. I don't know where it goes from there.
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In pic #4, you can see what appears to be a large ceramic resistor that has been completely cut from whatever it was attached to. I'd really like to straighten this car out. It purrs like a kitten but needs some AC work for sure.
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I didn't see a black cigar shaped sensor so I am a little worried. Oh and I tried Darrow's trick. It didn't work for me.
 

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This is the black cigar shaped sensor (from pic 1)....
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So its attached, all good there, shouldn't be your problem. I have no idea whats going on with the brutal custom wiring, kinda looks like the stock electric fan connector. Its not uncommon for people to upgrade that to improve their AC in hot climates. But that wiring is pretty brutal. The Factory Shop Repair Manual is online, if you are capable with wiring diagrams it shouldn't be too hard to figure out how it was all supposed to go.

Your heat problem is probably a dead or leaking VSV under the windshield washer tank.
 

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On one of my Corvettes, I just put an inline shutoff valve in one of the heater core hose lines, so even when the heater control valve was working it was still allowing enough water into the heater core to make it toasty during the summer. Once I did that, I had no issues... costs less than $20 (I got some really nice pieces)
 

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To clarify on Darrows point, the other sensor that can cause this is in the center console next to the Power Mirror adjustment switch. It's attached to the fan unit that vents above the ashtray in the back seat. If that is disconnected, the heater will only blow hot.
 

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Discussion Starter #11
Thanks Gus. I may look into that.

And thank you for clarifying Mercuralis. My center console was in the rear hatch. I dug it out and drove it in to work today. I actually made it both ways without sweating profusely. Now to convert to r134a...
 
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