Very Little Heat

[DodgeV10]

I currently have a 1990 Supra Turbo Automatic Tanny, I am getting no heat, where do I need to start to diagnos this problem. The AC works fine in the Sommer months. Please Help! Thanks

[bgrieger]

Start with the heater vacuum valve. A common fail point. It is beside the wiper motor on the passenger side on the firewall. Reroute vacuum to the nipple on top of the diaphragm can (this bypasses the electric vacuum switch that is usually the real problem), and see if you get heat. If so, you found the problem. They are a little spendy from Toyota (read: you will curse when they quote it), but they are a common failure at this age, so no guarantee a used one will suffice. I've gone years with it out, and in the spring, I put a golf tee in the vac line leaving it unplugged from the diaphragm so I can use AC.

[Dave's]

If you can DIY, then you may want to change the thermostat after checking that the switch is allowing coolant to the heater core. These are usually cheap and easy to replace. (under $15)

[Jeeves]

Dave, I think you're going the wrong route. The VSV is a VERY common failure point (and it's easier to test than a thermostat, you can move the valve with your finger to test it).