A/C Head - some things work, some don't

[Pauwl]

Based on the price of replacements, I don't want to order a replacement A/C 'head'.

I mean the unit that you set warm/cold & blower speed- not sure if A/C head is the right name.

Symptoms:

1) Fan speeds 1 & 2 don't work. 3& 4 are fine (blower just replaced as well)
2) Temperature works fine - cold & warm
3) Airflow up/down works fine
4) Defrost switch working fine.
5) AC button does NOT light up. My AC is also empty (I think), so I'm not expecting it to work, but the button used to light up.
6) If I have it switched to cold, cold air comes out of the TOP of the central vent (just above the A/C head), but warm air comes out the bottom.

I think I read somewhere that the fan speeds could have to do with a faulty bi-metal in the hood area, but can't find the reference anymore to check.

Any ideas would be great.

[ROG100]

Pauwl,
You need to trouble shoot the A/C system. I will email you a great document written by Wally Plumley to help you.
Once you know what is working and what is not I/we will be able to help you better.
Do you have a Mitghy Vac?
Roger

[Pauwl]

Thanks for that. Seems a really complete piece.
I don't have a Mity-Vac.

I'll start the resistor coil testing this weekend, and report back how it goes.

[Danglerb]

The mityvac or something like it is essential for messing with vacuum controls.

http://www.amazon.com/gp/product/B000FUMWTM

Its just a small grip operated vacuum pump with a gauge and some tubing, but it makes testing vacuum actuators and vacuum lines simple and easy.