1997 Explorer Climate Control Possesed !

[jrogerbeck]

I have a 1997 Eddie Bauer explorer with the SOHC engine and Automatic climate control. I have had the control unit rebuilt and done the heater treater repair to the broken blend door.. Its latest trick is as you drive around with the control on MAX AIR it switches between cold air and really hot air coming out of the vents . It runs about 5 minutes of each and doesnt seem to have any pattern. The only thing I haven't replaced is the heater control valve. Not sure if that's the culprit so any advice is appreciated.

 

[gmbroy]

Have you replaced the blend door actuator ? I need to do the heater treater repair myself . Did you do it or have it done

 

[jrogerbeck]

I did it myself. It helped to take the passenger seat out so I could lay on my back. It's a fiddlely job. It also is more difficult to seal the air box up after you get it back together than the instructions imply. Gorilla tape has worked the best for me.

 

[jrogerbeck]

More testing tonight. It shoots cold air out when you start the truck until the engine warms up. Then when you hit the gas hard it blows some really hot air while on the gas. Off the gas it cools down but not to air conditioning level. This seems like the heater control valve is always open and is circulating hot coolant thru the heater core all the time . Concur or disagree? Is this a vacuum problem or a heater core valve problem?

 

[Craigerz]

Vacuum leak. Heater valve should only close on Max AC. So you can visually inspect that it’s opening and closing at idle. Mine went out on a trip last August and had to zip tie it closed. We ran without AC for a few but with it still open it was like driving with the heater on. That was my side of the road fix.I’d say zip tie it closed to shut off all hot water running to the heater core and see what it does to eliminate that.

I’d say vacuum leak though. Sound like you’re losing vacuum when you hit the gas, shutting down the AC and when enough vacuum is there it puts all the flaps and what nots back to where they are set.

But the heater valve also runs off a vacuum so

 

[jrogerbeck]

So it was the blend door actuator which was broken off . However when I replaced the blend door actuator with a new one I still get an error and the blend door moves into winter mode and blows hot air. So for now I have removed the actuator and taped the blend door into summer positron and will leave i so until fall or i get a better idea.