No Heat ! 1989 c4
Thread Starter
Intermediate
Joined: Dec 2013
Posts: 30
Likes: 3
No Heat ! 1989 c4
All the blend doors seem to work, everything transfers fine, controller was panel was repalced and reads fine, haven't looked into it yet, maybe bad heater control valve? Seems to be stuck on ac and blowing actually colder than the ambient temp. 1989 c4 any quick checks ? Maybe a bad actuater motor for a blend door ?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Are the heater hoses hot where they go into the firewall? Is the thermostat missing?
Sometimes a plugged heater core will block the flow of water and that will cause the heater hoses to stay cool (relatively -- they'll get hot eventually).
Do you have the C68 (digital) HVAC system? If so, set the temperature to 90°. That should make it put out hot air no matter how the controls are set.
Sometimes a plugged heater core will block the flow of water and that will cause the heater hoses to stay cool (relatively -- they'll get hot eventually).
Do you have the C68 (digital) HVAC system? If so, set the temperature to 90°. That should make it put out hot air no matter how the controls are set.
Last edited by Cliff Harris; Oct 6, 2014 at 10:04 PM.
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
it's not un common for our heater cores to load up with small particles of Debris inside of the water passage's, As Cliff indicated the hose's should be Hot! if not a gentle back flush of the Heater Core it-self with a garden hose should cure this problem.
