joesgulfstream

took my 95 out fo a 45 minute trip out side temp. 27 heat worked fine ( auto heat control ). 4 hours later went home out side temp. 20 , no heat, coolent temp 204 average. mostly hwy. driving . what does this sound like ? THANKS

eodtech72

Just had a similar problem with my '89. Turned out the coolant level was low. Hope this helps....

pcolt94

There are two likely scenarios to that problem. A clogged heater core or the temperature door is not moving into the heat position. Sine you just had heat I would think it’s the temperature door problem. This could be anything from a door motor, programmer or the control head. These are the most likely component failures if it is a component failure.

I would first verify if the temp door is moving. If you remove the blower module in the top of the evaporator box (under hood) and look in there with a flashlight and have someone cycle the temp control from 60 to 90. The key has to be on, the environmental system can be off and the temp control button will still work.

If it is not controllable and the door does not move, the first simplest thing to do is to remove a battery cable for 30 sec and reset the system. It might come back and start to work again.

If this does not fix it, then much more in depth diagnosing would be involved.

jlr4115

You might want to look at my posts over the last 7 days. Am having the same problem with my '89. Got a lot of ideas from other members Mine is a work in progress. Have secured a used servo motor but still not corrected the problem. You could wire the door open for the time being. At least you would have heat but no a/c. Will keep you up to date on what developes, if you like.

Jim