Blower wont work for Heat/AC

[97Exec]

Hey guys,

I have a 2000 Merc Grand Marquis LS and the Blower for the Heat/AC has stopped working. It used to get stuck on high speed and whatnot. But nothing happens when I move the dial now.

It has a very similar (same) Climate Control dial/button layout as my 97 Town Car any Ideas?

Thanks again, Ian

 

[Town]

Hi Ian,

Sounds like the BMSC has failed. It provides a variable grounding for the blower fan to operate at different speeds. Often if the EATC is switched off (and BMSC has failed) the blower will still run.

The automatic temperature control system uses the EATC module that uses a BMSC (blower motor speed control) module to govern blower speed. We have the procedure to replace the BMSC in our Lincoln Tech forum here: http://lincolnforums.com/forums/threads/11627-Town-Car-BMSC-Blower-Motor-Speed-Control-replacement see post #2 for the 1998 thru 2002 Town Car models. I would think the 2000 MGM would be the same as the 2000 Town Car.

Good luck.

 

[TABBOOMA]

That's a pretty quick diagnosis without checking anything basic.

How about checking fuse 9 in the central junction box? Maybe start with the simple things first.

Check the BN/OG wire at the blower motor. It should have B+ when ignition switch is in RUN. That would check the fuse 9 circuit to the motor.

If you have B+ there, take the OG/RD wire to ground and the blower motor should run wide open. If not replace the blower motor.

If it runs you have problems with either the EATC module or the BMSC.

GL

 

[krauseheim]

A follow-up tale... I had a similar problem on my 2000 Town Car. Replaced the blower motor, and the new motor worked great, except for a minor detail. I could hear it just fine, but no air was coming out of any of the vents (heat, dash or defrost). After a day of puzzlement, we found that the replacement motor, even though "the book" said it was the correct motor for this car and several Fords, was blowing in the wrong direction. In other words, the heat, dash and defrost vents were inhaling, not exhaling. We reversed the wiring, and now everything is dandy. Chalk it up to experience.