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A/C "max" setting, '86 C-10

Discussion in 'Chevy Trucks' started by whwright, Aug 6, 2003.

  1. whwright

    whwright Member
    Messages: 39

    Hey guys.

    I've got my '86 Chevy C-10 running pretty good now, so it's on to the A/C system.

    I have the A/C blowing cold, but when you move the lever to "max" the fan doesn't blow any harder. All my other old GM cars blow harder on "max." Is this one supposed to as well?


  2. wyldman

    wyldman Member
    Messages: 3,265

    Basically all the "Max AC" setting does is open the recirculate door.This draws cool air from inside the truck,and recools it,increasing AC performance,and lowering humidity.

    Can you hear the door open ? Does the blower motor get louder ?

    You should be able to crawl under the dash and see and/or hear if the door is working.If not,maybe it's disconneted,or the diaphragm is broken ?

    It may be opening and on that particular truck your just not feeling the increase.The GM trucks weren't known for powerful blower motors.
  3. whwright

    whwright Member
    Messages: 39

    Once again, you have taken me directly to the source of the problem.

    The vacuum door was not moving at all. The hoses all looked good, but a quick check under the hood revealed that someone had unhooked it from the engine. I plugged it in where the snorkel vacuum door is supposed to be hooked up, and voila, the A/C magically blows harder on "max."

    It inadvertently fixed the next problem I was going to look into as well -- the cruise control works now too!


  4. wyldman

    wyldman Member
    Messages: 3,265

    One of these days you have ALL those vacuum problems sorted out.Glad to hear it was such an easy fix.

    Till next time...............;)
  5. 75gmck25

    75gmck25 Senior Member
    Messages: 119

    Just one comment - on my truck ('75 GMC) the max A/C (lowest temp) setting does affect the blower. If the blower is on a low speed, it goes to the highest speed when you push the temperature past its indent and go all the way to max cooling. It also switches the A/C to recirculate mode at the same time.

  6. whwright

    whwright Member
    Messages: 39

    The A/C control in my '86 truck will run the fan at lower speeds while in the "max" setting. When I was a kid (but I don't want to admit how long ago that was) my older brother had a 1970 Monte Carlo that had control like you're describing.