HEATER PROBLEMS
 

THIS IS IN AN 86 C10 PICKUP. HEATER HEATS OK, AC COOL OK. WHEN THE HEATER IS ON AND IN HEAT POSITION 80% OF THE HOT AIR COMES OUT OF A/C VENTS IN THE DASH AND COOKS YOU FROM THE WAIST UP. VERY LITTLE AIR COMES OUT ON THE FLOOR. WHEN YOU GO TO DEFROSTER IT DOESN'T BLOW HARDLY ANY HOT AIR ONTO THE WINSHIELD BUT BLOWS OUT THE A/C VENTS. VERY HARD TO DEFROST THE WINSHIELD IN THE MORNING. THE GM DEALER SAID THERE IS A VACUUM SELCTOR VALVE ON THE HEATER/AC CONTROL PANEL. HAS ANYONE EVER HAD THIS PROBLEM AND HOW HARD IS IT TO REPLACE. I'VE HAD THE CLUSTER OUT BEFORE BUT NEVER MESSED WITH THE HEATER CONTROL PANEL. AUTO PARTS STORES DON'T CARRY THE VALVE..DEALER ITEM. THE ONE IN MY 86 SUBURBAN HAS STARTED TO DO THE SAME THING ONLY NOT QUITE AS BAD..YET.
I'VE CHECKED THE VACUUM ACTUATORS AND LEVERS AND THEY ALL SEEM TO BE WORKING AND NOT BINDING. IDEAS??

Yes, the vacuum switch (I guess you would call it) at the control panel will sometimes develop a leak or break and will not pull the associated vacuum actuators to close and open the correct doors. Also, sometimes one of the vacuum hoses that go from the switch to the actuators get torn or pulled off and the same thing will happen.

First thing I would do is check all the vacuum lines from the canister under the hood all the way to the switch and from the switch to the vacuum actuators. Check the vacuum control actuators at the heater box to see if they hold vacuum. Then pull the heater/AC control panel and check the switch.

The switch in my truck doesn't work right either. I keep telling myself that I'm going to replace it, but I never do.

Hope this helps,

P.S. You don't have to shout (all caps), we can hear you just fine. http://67-72chevytrucks.com/board/ubbhtml/biggrin.gif

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Mike

1985 Chevy C-10
Mike's 73-87 Chevy Pickup Site

[This message has been edited by swervin ervin (edited 12-06-2000).]

Sorry about the caps. I'm new to this e-mail and bulletin bd. stuff. I'll check the things you told me about if I ever get another warm day off.(Probably not in December) I think this started getting gradually worse last year now that I think back. Also if anyone wants tips on converting their truck from R-12 to R-134A, I just did mine this past July. I can tell anyone the correct way to do it now that I've done it both ways. (right and wrong)

Thanks

Dave, I'd be 'all ears' regarding anything you could tell me regrarding the A/C conversion. I'm planning to do the same thing in the near future.


Contact me directly at xxxtonyhoward@msn.com if you'd rather. (Remove the X's)

Thanks.

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'87 3/4T Suburban / 502HT / Edelbrock MPFI /
Gibson 3" / GV overdrive / 3.73 - one strong trailer tug

Fellas,

I converted my truck from R112 to R143. Boy is there a difference in price and temperature. I replaced most of my A/C system on the conversion. My truck was parked for three years before I bought it. I replaced the compressor, condensor and the engine bay hoses. If you replacd the engine bay hoses, be sure and buy the new ones that have a sandwich "interior" plastic barier. This will help stop diffusion of the freon. Leaching is a big problem with old hoses. I had mine made at local hose shop for less than $100 bucks. The conversion is straight forward. The trucks A/C gets so cold with the fan in the lowest setting I have to turn it off even when the temperature is almost 100 degress!! City driving or highway driving the conversion works just the same.


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gchemist
1983 Custom Truck
TX Plates: "BAD BOW"
http://www.geocities.com/abetterchemist/