87 celica heat

im working on my buddy's 87 celica, and his heat is inop, sometimes works sometimes doesnt. Im leaning towards it being the temp door in the heater box. Im ust wondering if the doors are vacuum operated or if they are electronic. I havent dug into the car very deep to see whats going on, im just looing for some insight. Thanks.

My 86 does the same thing. I'm not sure what the problem is, but I can only get it to blow hot air when I get on the throttle while I'm in gear.
I can't just rev the engine, it has to be in gear and I have to be moving for it to work. I've been told it's a vacuum leak but I haven't found it yet. Good luck and if u figure it out let me know. :biggrin: lol

Read this post and follow the directions to resolder the pins,they won't appear to be loose but it's called solder bloom,or something like that.
http://www.automotiveforums.com/vbulletin/showthread.php?t=159202