Stuck in defrost and floor

[posdeer]

I have a 98 GMC Sierra 1/2 ton 4wd with a 5.7. my vents are stuck on defrost and floor, I've tried 2 new mode actuators from a parts store with no luck. All they do is wiggle a little side to side when changed on control module. I've tested the plug to the actuator, pin 10 has 12v, 9 and 8 have smooth continuity. How do I know if it's the control module? Is there any vacuum controlled actuators on this system?

 

[posdeer]

Anyone have an idea? I just pulled the control module and added a relay which from what Ive read should fix it. I do have vent and floor now but still no AC or recirculate.

 

[Jeenyus_eh]

Your AC could be not kicking on for a variety of reasons. Have you ever seen it work in this truck?

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[GMCTRUCKS]

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