Ive checked out everything I can think of and I am at a loss.No heat and the AC actually doesnt seem to be as cold anymore when I turn the **** back.no matter what setting its on the air seems to be the same temp coming out.While the AC is running or the Heat is running the High Side is Hot and the low side is pretty cold like its supposed to be on the ac but the heater core lines coming through the firewall are also pretty hot.No matter what its set at it I get the same result!No Heat or AC.Is there a way by chance to test the Blend Control Switch?(This is what the Haynes Manual refered to it as)Its a 98 so in 7 years is it likely that this switch has gone out?

 

BrianXLT,
I have a '99 F-150 but I followed the instructions in this thread https://www.f150online.com/forums/sh...d.php?t=212548 and it worked for me, might be the same for a '98. While you have the actuator motor (Blend Control Switch) removed you can use a mirror and a flashlight to take a look at the blend door where the actuator shaft goes to see if the door is broken. My blend door was broken and I just repaired it this past weekend. BTW, the screw mentioned that is located on the back of the duct is a bi**h to get to. Good luck...AlanT

 

EVEN DEEPER MESS!!! My actuator itself is nonfunctional and the door looks just fine.I have 12v power to the actuator from the fuse panel but no motor function.I ohmed the three leads that go to the dash control and they all ohmed out!I went and bought a new switch and a new actuator from my local dealer and the same problem!!! Has power but no function! I am at a loss!

 

BrianXLT,
Sorry to say but this exceeds my knowledge on this problem. I wish it had been a bad actuator motor as that would have been an easy fix. Someone on this forum will come along shortly with the answer you need, seems they always do based on what I've read the short time I've been a member.

AlanT

 

The Dealer gave me the wrong Actuator.Upon closer inspection I noticed that the slots on the arm were different and that it was on the wrong side of the assembly.They game me one for a 98 Expedition!It has the same connector for it but I think the pin organization is different(where the power,ground and control wires are located on the plug)I got the right one home and hooked it up and all is well.WHEW!!!! That was close! Thank you for the tutorial link Alan I really appreciate your help and yea that back screw is a pain in the a**.

 

I'm glad you got that straightened out and happy for you that it was just the actuator motor. I had to replace the blend door and it was just a wee bit more work. Glad I could help out in any little way. Aren't these forums great?

AlanT

 

Hey guys. Thanks for the info contained in this thread. Saved me alot of money. Excellent instructions on replacing the blend door actuator motor. And, I agree, that one little screw on the drivers side is a son-of-a-gun. When I pulled the old motor out and shined a flashlight in a mirror to look at my blend door mechanism, it looked cracked. I took my chances and went ahead and installed the new motor and it works fine. Hopefully it will stay that way, but we'll see. Any ideas on repairing that little dude through the actuator motor drive hole? Maybe it will be ok for a while, and I really, really don't want to have to tear the dash out of my truck.