Possessed '95 Suburban (6.5)

[forbey]

OK, I know when Spring is here. My heater/air conditioner switches from A/C to heat. No fooling!

The HVAC unit, technically, does not work. I've tried replacing the control board with no luck. However, when the vehicle is moving it does allow cold air or hot air into the cab.

Problem is, for the past 3 years, it is backwards. I have to shove rags in the floor vents to keep the cold air from blowing up my legs in the winter, and at present, I have to run down the highway with all the windows open to let out the hot air.

Someone told me there is a "reset" button, which should allow me to rest the vent doors, but they couldn't tell me where it was. Hopefully, they weren't trying to sell be a box of grid squares! :D

This may also be a vaccuum hose problem.

Any suggestions would be greatly appreciated.

Thanks,

forbey

[Robyn]

On the 95 there are 3 servo motors that control HVAC system.

One motor controls the "BLEND" door. This controls the temperature of the air coming into the passenger compartment.

Another servo motor controls the particular vent that the air comes from.

The last motor controls the flap that allows either outside air or recirc to be used.

The little motors are about the size of a cigarette pack and mount on the HVAC unit.

The recirc motor isd in a bitch of a place up between the firewall and the HVAC box right about under the passengers feet.

The Blend motor and the other one are accessable, one is near the LH end of the box and the other is on the back side about the middle I believe.

These little motors must be programed as to position. A failed control board and replacement will not always guarantee that the motors will work right.

You need the GM manual to go over the diagnostic procedure on these.

There are no vacuum hoses on these units, its all electronic servo controls.

Hope this helps some.

Robyn

[forbey]

This helps a bunch. Now to crawl my large self into the passenger foot area and get to looking.

Thanks,

forbey

[DaveBr]

If it helps I always pull the seat out if I am working under the dash for extended periods. Cuts down on trips to the chyropractor.