AC/heat not working properly...help

[Narco]

My AC and heat are either all or nothing. If it's 90 its hot or 60 its cold. There's no in between. If you adjust it to anything in between the temp stays. If I start at 90 and dial it down to 78 it stays at 90. If I start at 60 and roll it up to 72 it wont warm up.

Tonight I had the shit set on 90 and it never blew hot at all...only cold air was coming out despite being in the car for half an hour. Any ideas?

 

[Young28]

try putting it in defrost to see if it warms up. in my white truck it will warm up faster in defrost then blowing on your feet or at your face.

 

[Narco]

i tried...it was not blowing hot at all...wasnt even warm.

 

[Narco]

now its working again...pissing me off

 

[yargnits]

what's your coolant level? does it heat up when you rev the engine?

 

[Narco]

no. coolant level is fine. im wondering if its some sort of actuator that opens or closes to allow heat/cool air in

 

[yargnits]

If that one guy was still here he'd probably say you fried the BCM when you modified your truck!

---------- Post added at 11:14 PM ---------- Previous post was at 11:08 PM ----------

I found this. It might help you poke around. The guy's describing his Silverado...

"I think its fixed a couple more weeks to be certain. Two weeks ago I replaced the drivers side temp actuator GM part # 89018365, it was just under $200 with tax from the dealer. You can get it thru www.gmpartsdirect.com for almost half that price now that you have the part #. Take off the duct shroud ( 4 screws ) and the actuator is right above the hump in the floor, only 2 screws & pull down. You can fell the spindel or shaft that connets to to flapper that lets in the heated air, open and close manually with your finger tips an you can hear it open & close. Line that shaft to the opening in the actuator and reinstall the 2 screw. I plugged the new one in first and started the truck to watch the actuator turn to the close flap position (no heat) which is what I had manually put the flap in. It was a very simple job 10-20 minutes. I like to know what the dealer would have charged, probably pretty high. I also found out when I got the part that their are 3 or 4 actuators in that system. The passengers side is above the drivers at the top side or the duct (under top of dash), hope that one never goes, and theirs one for recirculation door and I think their is one more somewhere in their. hope this helps. "

 

[teroma25]

Yeah it sounds like your actuators. Are both sides the doin' it? rear? When I was havin' problems with mine I read somewhere that they sometimes stick all the way open or closed, sounds like yours. Also low volts caused problems before making them stick.

My fronts were blowing all stupid back asswards after drainin' the battery one night. Shuttin' the kon off and restartin' fixed them when they acted up. My rear actuators are toast, both need to be replaced, but they're expensive. I jammed a screw through each one for the winter in the hot position. Once I need A/C I'll turn them all the way opposite of they way they are now and jam a screw in'em again.

 

[Narco]

the rears seem to be ok. the fronts both seem to be out. i reset the battery and now theyre working again. very off. so the consensus is its a bad actuator? whats the diff between the actuator and the blend door? how could i tell which one is the culprit? anyone have pics of this?

 

[teroma25]

The actuator is what moves the blend door. When you remove the 3 little screws that hold the actuator in, you can manually move the blend door and check it. If you leave the actuator plugged in while you have it out and turn the temp switch cold or hot, you should be able to see the actuator moving. I highly doubt your blend door is at fault, most likely the actuator has given up by the sounds of it.

For some reason I can't seem to attach a pic, but if you go to any of the online parts store sites they all have pics of the actuator.