Blower Motor is possessed

[ncharge]

The blower motor on my 99 suburban comes on when it wants to even after the key to the vehicle is removed. It has no problems during run time, all speeds work etc.

You can shut the vehicle off and it will shut off and a few minutes later it will come on and run your battery dead. The lights for the AC come on as well but no other accessories come on, no radio etc.

Multiple Choice:

A. Ignition Switch
B. Wiring Harness
C. Blower Control Switch/Module
D. Take Vehicle to ghost busters?

Any advise would be appreciated. It does not do it all the time, but will definitely do it when you don't expect it and run the battery dead.

Thanks

[MT-2500]

Originally Posted by ncharge

The blower motor on my 99 suburban comes on when it wants to even after the key to the vehicle is removed. It has no problems during run time, all speeds work etc.

You can shut the vehicle off and it will shut off and a few minutes later it will come on and run your battery dead. The lights for the AC come on as well but no other accessories come on, no radio etc.

Multiple Choice:

A. Ignition Switch
B. Wiring Harness
C. Blower Control Switch/Module
D. Take Vehicle to ghost busters?

Any advise would be appreciated. It does not do it all the time, but will definitely do it when you don't expect it and run the battery dead.

Thanks

Auto or manual heater control?
When it does it tap or unplug relays and or blower motor module.

[ncharge]

Originally Posted by MT-2500

Auto or manual heater control?
When it does it tap or unplug relays and or blower motor module.

Auto heater control. Just the 2 knobs for fan speed and tempature, 2 buttons for recirclulate and A/C.

I started diagnostics with the ignition switch... key out and the fan starts... tap the thumb ring on the ignition switch and it will shut off and then generally come back on. I just can not figure out why it is only the fan or air controls coming to life if it is the ignition switch. I would assume if it was having a problem it would turn on everything. Is my thought process wrong? Can it just turn on the A/C? I have not pulled it out but my thought is you have the ignition switch, going to the harness. Doesn't the switch have 4 positions, AUX, Off, Run, & Start. If it was in any of these positions would it not power all of the stuff in that position?

Thanks for the help.

[MT-2500]

Originally Posted by ncharge

Auto heater control. Just the 2 knobs for fan speed and tempature, 2 buttons for recirclulate and A/C.

I started diagnostics with the ignition switch... key out and the fan starts... tap the thumb ring on the ignition switch and it will shut off and then generally come back on. I just can not figure out why it is only the fan or air controls coming to life if it is the ignition switch. I would assume if it was having a problem it would turn on everything. Is my thought process wrong? Can it just turn on the A/C? I have not pulled it out but my thought is you have the ignition switch, going to the harness. Doesn't the switch have 4 positions, AUX, Off, Run, & Start. If it was in any of these positions would it not power all of the stuff in that position?

Thanks for the help.

If taping ign switch doe it then work on ign switch end.

[777stickman]

A note on ignition switches. On my '98 Sub there are 5 different contacts in the switch. One of theses contacts powers the HTR-AC fuse (and some other stuff) in the I/P fuse block. If that fuse is getting power with the key off it is most likely a bad ign sw.