Blower speed controller diagnose, pls help!

[770mark]

I've read a ton of posts, but none really covered what I'm finding.

It's a 2000 Explorer with climate control. The front fan does not blow at all. The rear does and works fine. The A/C cycles fine, but regardless of the control settings, no fan.

I removed the fan connecter and it shows 14.4 volts, so figured it was the fan motor. I plugged a new motor into the harness before installation just to be sure that was it and still no fan! I checked the new one and it works fine w straight battery voltage, but not when connected to the car's harness despite showing 14+ volts at the connector.

Does the controller adjust amperage vs voltage on this system? Any help you can offer on diagnosing this would be a big help...

THANKS!!

 

[budwich]

In "actuality", it provides "varying paths to ground".... thru a "resistor bridge" (although maybe a bit more "solid state")... thus varying the current. Your problem appears to be the "classic speed control busted" problem.