I have a '89 Trooper - and recently it seems that the heater/and A/C are neither hot or cold when I try to use either. The fan works in both cases.
It looks like there was a previous post similar to my question - but no follow-up.
What would cause this? Is it a releatively simple fix, my Hanes manual dosen't seem to answer.
...hope I can get this done before our Canadian winter starts.

thanx.

the only thing i would check is a blockage on the intake vent under the dash such as paper or a candy wrapper.

thanks for the idea - I checked it out though and nothing is stuck in the vents. As well the coolant is topped up. Perhaps is there a flap that controls heat and a/c that is staying open, causing the only cool air to come out?

same proplem cold air blowing only - no heat now car is overheating - whats the next step

I have a '89 Trooper - and recently it seems that the heater/and A/C are neither hot or cold when I try to use either. The fan works in both cases.
It looks like there was a previous post similar to my question - but no follow-up.
What would cause this? Is it a releatively simple fix, my Hanes manual dosen't seem to answer.
...hope I can get this done before our Canadian winter starts.

thanx.
I believe that Early Troopers have a valve that controls coolant flow through the heater core. Newer models utilize a core that always has coolant flowing through it and a flapper valve to control the hot air flow through the heater core. Could be that the controls in the cabin have become disconnected from the throttle valve or some maybe something is causing a blockage.

Also have you verified that you have proper refrigerant pressure in the AC system?

thanks for the idea - I'll check it out, I've also been told that it might just be the thermostat needs to be replaced...I'm going to try this, haven't had a chance though as the trooper has been in the shop w/ bigger problems.