Blower Motor probelms

[dscowell]

The blower for my climate control is not working. I replaced the blower motor and blower motor resistor. When I turn the truck to accessory the motor works, once I turn my engine over I blow a fuse. When the truck is on and the climate control is turned off it will not blow a fuse but once I turn it on the fuse gets blown. What could be causing this? The new motor I got does not have a plug so I had to hard wire it in. Is it possible I have the two wires switched up and it will work fine on accessory but not with the engine running?

[dieseldoc]

Hmm.....sounds like you have something out of order.
But really it shouldn't make a difference.
As the motor get power from the same source.
Very interesting.....

[dscowell]

Switched my wires around and got the same result. I don't understand how it's working on accessory but not when the engines on. I'd think if it shorted out somewhere it would work at all. If there was a vacuum problem it wouldn't work either right? If no one has any quick easy suggestions I'm probably just going to go to the shop. This is busted and so is my stereo.

[Brian]

Just a WAG, but could your alternator be over charging and blowing the fuse?

[Jim]

When you changed the fan could you have disrupted some other wiring?

Does it happen if you unplug power to the fan's motor (at the motor)? (does it happen with a completed circuit vs does it happen with an open circuit)

[TJS86TOY]

One possibility is that the aftermarket motor when running on ACC ignition on is lower speed because no charge is drawing lower amps , then once alternator is charging blower may be drawing more amps. Any data on the motor such as FLA, RLA, ? may need a larger fuse.

[dscowell]

could your alternator be over charging and blowing the fuse?

Did not think of that. Earlier my dome,radio and i'm assuming blower fuse all blew at once. The dome fuse is the only one that hasn't blew again but the other have.


When you changed the fan could you have disrupted some other wiring?

Does it happen if you unplug power to the fan's motor (at the motor)? (does it happen with a completed circuit vs does it happen with an open circuit)

No other wiring should have been disrupted. There were a few vacuum lines and the coolant bottle in the way but they were not damaged. Some wiring could have been damaged when I replaced my dash but I was careful not to damage any.

When I unplug the motor the fuse pops when I turn it "on" It did take longer for the fuse to pop then it did when the motor was plugged in. I know some people suggest to just hard wire the motor in and bypass the plug. Could the plug be causing this?


One possibility is that the aftermarket motor when running on ACC ignition on is lower speed because no charge is drawing lower amps , then once alternator is charging blower may be drawing more amps. Any data on the motor such as FLA, RLA, ? may need a larger fuse.

This is the motor I got. Not sure if this helps or not.
http://www.autozone.com/cooling-heating-and-climate-control/a-c-heater-blower-motor/vdo-a-c-heater-blower-motor/141580_0_6648

[Jim]

When I unplug the motor the fuse pops when I turn it "on" It did take longer for the fuse to pop then it did when the motor was plugged in.

Then, direct wiring your motor will still result in the fuse pop. Does any other component stop working when the fuse blows? If yes, you'll need to track things down and fix it - motor connected normally or bypassed. If no, you could wire around the issue.

Do you have the factory wiring diagram for the vehicle? What make/model/year/options is it?

Regarding downstream circuits: For my fuse blow issue (tail lights go out), the dash lights are a downstream item (also fused) from the tail light circuit. So, when my tail lights fuse blows, I also lose my dash lights (which is a nice indicator I have no tail lights).

[dscowell]

Then, direct wiring your motor will still result in the fuse pop. Does any other component stop working when the fuse blows? If yes, you'll need to track things down and fix it - motor connected normally or bypassed. If no, you could wire around the issue.

Do you have the factory wiring diagram for the vehicle? What make/model/year/options is it?

Regarding downstream circuits: For my fuse blow issue (tail lights go out), the dash lights are a downstream item (also fused) from the tail light circuit. So, when my tail lights fuse blows, I also lose my dash lights (which is a nice indicator I have no tail lights).

I do not have a wiring diagram nor the skill or time to fix it.

The blower fuse I believe is only connected to the blower. When my dome when out my gauge lights and tail lights went out. I haven't noticed any other parts of my truck malfunctioning.

I guess this being the case I'll have to bring it to a shop. My knowledge of wiring is minimal and with how the weather here has been lately I need to get this fixed relatively quick.

Thanks guys!

[dieseldoc]

If the truck is in CO.
The best electric shop in town is Lakewood Auto Electric
There on Colfax half block north on Wadsworth.

Sounds like you have a grounded hot wire.
Something has pinched or rubbed through.
I hope you can get it handled.

[Spieg]

Something has pinched or rubbed through.

^^Ditto.
Seems like the most likely cause, although there is an off chance the switch may be grounding internally. To be sure, maybe do a continuity test between the blower power wire and ground (while everything is powered off of course). Unfortunately this means you've probably gotta pull it apart again. Can you access the back of the switch (terminals) without pulling the dash? I'd try to bypass/disconnect the original wire and run a new wire to the blower motor (don't know if you can do that without pulling the dash or not). Maybe put a loom/shield over the wire this time...