Blend door

[PrixieGirl69]

Hey i got a 1999 pontiac grand prix GTP, recently my a/c and heat has been blowing out of all vents and i cant change the direction of the air flow, i can change the speed of the fan tho, is this the blend doors? Also when i have the air on once in awhile its skweeks then stops. Could someone please tell me how to locate the doors and a picture if possible of it in the car

 

[Anthony Smith]

the blend door actuators give you the change over from hot to cold. The vent mode as far as defrosts, dash vents, floor change over is controlled by vacuum from what I remember. Check the small vacuum hose coming out of the vacuum tree on top of the supercharger. I had mine unhooked because I couldnt figure out what it went to when I put the engine back in my car and it did the same thing.

 

[PrixieGirl69]

Okay is there anything else i should check too if thats not problem

 

[CTKGP09]

it connects to a little box under the dash by the passenger side footwell, check both sides of the tube

 

[Scottydoggs]

the line off the supercharge tree that leads to the pass side fire wall, then it runs down the fender and under the fuse box, some cars have a T under the fuse box some dont, one side runs into a wire harness to inside the cab under the fan box, if you pull the carpet down you can see the wires, then the vac line runs to a bxx behind the dash. then to the vac pumps that work the air flow direction.

if you find a T under the fuse box the other side runs across the rad support and then under the driver side head light to a vac ball.

you want to follow this vac line from the sc top down and look for a crack in the line.


if you cant find any breaks in the line.

follow this thread http://www.grandprixforums.net/thre...acement?highlight=change+blend+door+actuators to get the dash open on both sides, then car running change air flow direction. watch the two round parts in the first diagram, its what changes air flow.

if they move but nothing happens, a linkage part broke, they fail on there own.


round part with a line to the top and the arm pushing out to linkage is what you want to watch, theres one on both sides of the dash