'86 GTS Heater Problems

[NBKarnage]

Ive got no heat coming out of the vents even when the car is at temperature, I've done a good amount of troubleshooting and found that the problem resides with a Bypass damper that's located just below the ashtray area of the console. The damper always stays open which then grabs air directly from the upstream duct work and bypasses the heater core...also, the 3-way mixing valve located beside the brake cylinder stays in the closed position which cuts off the hot water to heater core, regardless of where the tempeture slider is.

I've had the odd occurence of the heat coming on, and the last time I did I pulled over and poped my head under to see the damper was in the heater core path position, so then I jumped out and got the girlfriend to modulate the temp controls while I looked at the mixing valve and it was working perfect...got back in and 3 minutes driving down the road it was freezing air again.

The climate controls are obviously looking at some sensor that is saying a false reading; is there an outdoor temp that it uses so if it thinks its too warm out it will close off the heat automatically...

any help is needed as I'm freezing

-Neal

[wil_wil2]

Your problem lies in your coolant flow valve(the one beside the master cylinder), it is most likely slipping. I would recommend changing it out, as it is a very common problem on the 4th gen.

[allblackalltrac]

actually I'd say your problem lies in the heater control unit itself...see link

Toyota Celica Online :: View topic - Good ol' Heater Problem

I have a bunch of repaired heater control units if your in need of one just send me a PM or email

[wil_wil2]

I have never personally encountered that problem before, but I should remember it for future reference.

[NBKarnage]

Are you F-ing kidding me...why the hell didn't that link come up when I googled 2 weeks ago...I spent most of Saturday finding that exact problem...WOW! I didn't resolder it but just clean up all the terminal/connectors with contact cleaner...I will be resoldering them for sure even though my problem is resolved.

Tons of thanks for the link, it should be #1 on google query if Celica + Heat come up!

Cheers to warmth,
-Neal

[ydeardorff]

The link is dead, did anyone save it as a document?

[Rick89GTS]

Until those links come back up, here's the quick fix:
alltrac.net :: View topic - 4th Gen HEATER QUICK FIX