The air control in my car works fine for the first 3 settings, but the last and highest setting doesn't work. I try and turn the air up all the way and at the highest setting it just turns off. I'm hoping this is a relatively easy fix? Any suggestions? Thanks.

- Jim

Not entirely sure on 96-99'*, but I think there is a fast speed fan relay that you can check that applies full power 12vdc to fan for high speed. A 96-99 GH should be coming in soon.

It'* either the switch for the printed circuit board that mounts into the blower housing. I fought this on an old 97 Cavalier. It ended up being that printed circuit board. I found it by process of elimination.

You have manual air conditioning? Is that right?
I'll look in my 98 service manual.

In the MaxiFuse Relay center in the middle of the firewall
There are 8 slots on the bottom for relays. The 4th from the left is the high blower relay for a manual AC car. The left relay is AC clutch, then HOrn relay, then Blower motor relay (low speeds through resistor set in the blower housing area), then the high speed relay. The two at the right side are high speed cooling fan for radiator, then low speed cooling fan. On my diagram the two holes between high blower and the high radiator cooling fan are empty.

Hope that helps! I had an AC relay fail on a hot day when I was in Cincy sitting in mall parking lot running the air to keep the kid cool. It was easy troubleshooting once I got home because I could switch relays!

Note the relays in there may be the same part number and you can switch two to see if replacing the high blower relay makes it work. E.g., #7 from the right is the horn relay. Use a knife underneath to lift the tab that catches to keep the relay from coming forward and pull it out toward you.

high speed does not go through the resistor, as mentioned in the post above, it'* a direct feed through the high speed relay.

Check the relay for functionality. Especially check the contacts. Our cars have a habit of getting a little corrosion in there.

Is it worth checking the relay for the Pontiacs?

Hi - have not been here for a while,and I just saw this topic.

I have the same issue, and exact same car.
Obviously, the best thing is to fix it, but just to add:
I discovered that if I stop the dial between the high setting and the next-to-highest setting, the high speed air will engage.
This is my work around until I get it fixed (will that day ever come?)

Sounds like your speed changer switch is failing.

I decided to take the car into the garage to have them fix it. There were a bunch of little things going wrong so I gave up. Turned out there was a broken belt that needed replacing. Now the fan works fine so I'm happy.