Heater doesnt work
Thread Starter
Instructor
Joined: Dec 2010
Posts: 138
Likes: 1
Heater doesnt work
I have an 87 Coupe. Automatic.
I have the C68 Electronic Climate Control. The unit works and has been rebuilt.
Also, my AC and Defroster works, but there is little to no heat.
What is the best way to go about troubleshooting it ? And possibly fixing it ?
Any links, other articles are fine with me. I want to get headed in the right direction.
Thank you,
Harry C.
I have the C68 Electronic Climate Control. The unit works and has been rebuilt.
Also, my AC and Defroster works, but there is little to no heat.
What is the best way to go about troubleshooting it ? And possibly fixing it ?
Any links, other articles are fine with me. I want to get headed in the right direction.
Thank you,
Harry C.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Check the heater control valve between the tubes that go into the firewall on the passenger side. There is a valve there that bypasses the heater core when you turn on the A/C. It is controlled by vacuum. Make sure that valve is switching when you go from A/C to heat. You should be able to see a change in the position of the lever on the side of the valve. Since it's vacuum, the engine has to be running to do this test.
Here's a picture from my '86 shop manual. Note that this picture will give you an idea of where this is located but that is NOT what my car has in it. The valve in my car is attached to the lower tube very close to the firewall. My FSM has several pictures of carburetors, so I think they were just picking something close to put in the manual...
Here's a picture from my '86 shop manual. Note that this picture will give you an idea of where this is located but that is NOT what my car has in it. The valve in my car is attached to the lower tube very close to the firewall. My FSM has several pictures of carburetors, so I think they were just picking something close to put in the manual...
Team Owner
Joined: Jan 2003
Posts: 20,254
Likes: 221
From: Summerland B.C. Canada
The door and the valve are your likely suspects.You can remove the blower control module from housing and have a look inside, while someone switches from cool to hot. If the door is working, you should see it moving.
Same goes for the valve on heater core line.
Here is all the HVAC info from my 86 FSM.
http://members.shaw.ca/dankai/HVAV'S.pdf
http://members.shaw.ca/dankai/HVAC%20Electrical.pdf
