rear AC blower question

[aggiedave98]

My rear AC on my '89 suburban only works on high. I figured it was the restistor.

I finally decided to hunt it down (to find out it was really easy to find, but w/ the manuals you can never figure out where stuff is) and tested it. The resistors are in tack. I checked it w/ my ohm meter. There are actually 2 in series for some reason.

I then tested the voltage at the plug for the resistor and when the rear blower is on low, I get 12 volts there.

So what the heck is wrong w/ my rear AC on low??? High works fine.