Expert: Roland Finston - 1/11/2012

Question
Blower motor not running again. It ran after checking for voltage and spraying a little contact cleaner in the the clips. Stopped the next day. I checked the fuses and relays again - all good. I do have 12v on the dark blue wire to the module. Jumping 12v to the motor make the blower work. When i call for power on the climate consle, I hear a slight sound of a vent opening or closing behind the glove box. And same for turning off the power.
Where should i look next. Thanks in advance.

Answer
History:Looking guidance once again. No front blower, no heat in my 05 Pacifica w/ auto climate control. Control display looks and runs normally. Checked fuses - good. Switched relays - good. Replaced Power Module - no change. Could it be the fan motor? Checked continuity through fan (black and green wires)and read 0 ohms.
Any other test I can use to pin-point the problem?
Thanks in advance.

Answer
Hi Jason,
The manual shows there to be a front blower motor relay which you could touch/listen for to see if it actuates when a helper selects the blower. Then check to see if fuse 42 might have a subtle crack in its wire, and also verify that it is getting power from the blower relay on one pin of the fuse socket when the blower is requested. Check that 12v appears on the dark blue wire at the blower module plug, similarly. Try a direct 12v jump to the blower motor plug at the module to check the blower motor. Somewhere along that chain something is faulty. Let me know. Usually when that module fails the motor runs continuously at high speed but maybe not in this case.
Roland

Well, Checked my power readings and all were good. Jumped 12v to the blower motor and motor works fine. Sprayed a little contact cleaner in the wire harness clips and presto, Working blower motor with all the speed controls. Thanks and stay well in 2012.
End History

Hi Jason,
I would check as to whether you have any voltage coming out between the pins of the blower motor power module's socket that connects to the 2-wire plug for the blower motor. That voltage should vary with the requested fan speed. If not, then either the module is bad again, or the dark blue/light blue wire from the ATC control plug pin 7 to the blower module plug pin 3 is flakey as that wire is what communicates what voltage the module should put out to the blower motor. It may be that the blower motor is drawing too much current and has blown the module, is the last possibility. So check the above in that order and see what you find.
Roland