Vent Blower

[KMac]

When addressing this issue with my car, in the vacuum line there was a "t" with a filter type piece in it. My dad and I took it apart and cleaned the filter, which solved the problem, but only for a short while

 

[GP403]

The relay we're talking about is a little metal box about 1" by 2" or so, should be located in front of the blower box somewhere IIRC. Will have a couple different plugs w/ several wires going to it. Mounted w/ two screws(?)

 

[rev. 3:11]

Make sure the vacuum check valve hasn't gone bad.
They are the little black/grey pancake filters in the vacuum lines. They are cheap & available at NAPA, A/Z etc. The particular check-valve for the vents is in the engine bay on the firewall (I think). When these give up the ghost the vents bow onto the floor by default. Also check the vac line itself for dry-rotted rubber.
HTH!

D 8)

 

[BACKSLAP]

your missing vacuum going into the vehicle, the door is default set to blow defroster/floor until vacuum is applied. trace that vac line, easy to do really, crunch under your dash and start looking at the colored vac. lines, when i get back to my shop ill post the color scheme for you, i ferget off hand. sorry

 

[85 Cutlass Brougham]

Okay, here is how I see it. First off, the default position for the air doors is the defrost/heat bi-level mode on these cars for safety reasons, and that is where it is stuck. The fan motor is fine since it is blowing. If the relay is bad, it will have no air blowing at all. If the fan motor resistor is bad, it will only work in high as it cuts power in every other selection, but has no effect on high. So, it is likely the purple vacuum hose that is the main feed to the vacuum mode selector switch is broken under the hood, or some other vacuum related issue. The purple line is the outlet from the vacuum storage cannister. I would also check the inlet to the cannister by unplugging it and putting your finger over it. If it sucks, the problem is not in that line, but in a part of the system that comes after it. Check the ball next by unplugging the purple outlet line and seeing if it has vacuum on the outlet side with your finger. If that is good, trace the purple line to check for cracks. Repair any cracks with a piece of small vacuum hose, which can be cut from the wiper washer system in an emergency. If you find no cracks, try using a vacuum pump to test it and see how long it takes for the vacuum to drop. If you can't get it to hold at all with the pump on the purple line, there is a problem in the lines somewhere and you will need to trace them. It can also be a bad vacuum diaphragm, but check everything else first as these are a b*tch to fix, some requiring the dash to come out.