I have a '98 Bonneville SE with the automatic push button HVAC controls (digital readout) and the other day my blower motor stopped working. The display screen shows it should be running, but the fan does not work.

So far I have done the following.

Manually bypassed the blower fan with 12V and it works fine.

Checked all the fuses and all are in good condition.

I pulled the blower control module out of the blower box. Now here is my question. How do I diagnosis if this part is bad, or if it is getting an incorrect signal?

Here is what I saw on the plugs that go into the blower control module (while unplugged) with the ignition ON and the blower / heat turned ON per the display screen:

Red Wire: 12V
Purple Wire: 1.86V
Black Wire: 0.05V
Grey with Black Stripe: 8.7V

Here is a pic showing the plugs I am referring to:


With the ignition and blower off, the Purple/Black & Grey with Black all go to 0V.

Can anybody help???

Also I pulled a few out at the junkyard of similar cars (Olds, Buick,etc.) but none of the control modules looked the same as the one that came out of my '98 Bonneville. I know some of the years had a "high speed" relay, but this year supposedly was controlled entirely by the Blower Control Module. Do I need a '98 specific controller??

I really didn't want to have to buy new cuz I'm broke, and my pregnant wife is mad at driving a car with no A/C blower. Thanks!!