2000 limited AC front blower issue

[atis]

My front AC/heater blower is not working... the rear works fine. I have replaced the blower motor resistor and that did nothing. It went through a phase of turning itself on adn off when it wanted too before it finally stopped all together. I tested the plug for power with a meter... I get a few mil amps when in the off position, 11.4v on position 1, 2, 3 and 11.7v at max... so I bought a new motor and plugged it in... it started on 3 for about 3 seconds and then stopped... nothing in any position... what gives??

2000 tahoe limited (5.7L)

 

[JKmotorsports]

Since you have a meter, try these flowcharts. Hopefully this will help solve your problem.

Blower control system check

Symptom Diagnostics - Blower motor inop at any speed

Good luck. Let me know how it turns out.

 

[atis]

dumb question... the blower motor relay high is the relay under the dash next to the blower motor resister correct?? My repair manual sucks....:nonod:

and it doesnt show which is the C1 or C2 etc... i have the relay from under the dash out... I have "tone" between 30 and 87a and I pulled the fan motor and I get tone across pos and neg motor connectors.... checked the 50a fuse under hood... its good, so is the one by the drivers door...and I have now replaced the switch on the dash (fan speed) and that didnt do a darn thing either.

 

[JKmotorsports]

dumb question... the blower motor relay high is the relay under the dash next to the blower motor resister correct?? My repair manual sucks....:nonod:

and it doesnt show which is the C1 or C2 etc... i have the relay from under the dash out... I have "tone" between 30 and 87a and I pulled the fan motor and I get tone across pos and neg motor connectors.... checked the 50a fuse under hood... its good, so is the one by the drivers door...and I have now replaced the switch on the dash (fan speed) and that didnt do a darn thing either.

The high relay should be on top close to the resistor. Sounds like you have the right one.
C1 should be the gray plug with a purple wire, which is the motor feed ( +12V). C2 should be a black plug with a blk wire, which is ground.

 

[atis]

well I got desperate to fix it so I have replaced the following;

Blower resistor
Blower High relay
Blower switch (inside the dash on main controls)

all to no eval... still nothing.... how do I test the motor itself?? I got tone by touching the pos and neg on the motor... I think I will hook up one of my 12v plane motors (radio control) and see if I can get it to respond to the switch... any ideas?

 

[JKmotorsports]

Have you checked to make sure you had a good ground to the blower motor?

 

[JKmotorsports]

I think I will hook up one of my 12v plane motors (radio control) and see if I can get it to respond to the switch... any ideas?

It's not brushless, is it?

 

[atis]

no its not brushless, but my blower motor has both the pos and neg attached to the plug...and 5 screws mounting it to the box... I tried to replace it but no one carries it (autozone, advance auto)

 

[atis]

I have power (12v) at the Blower Relay (which comes directly from the panel under the hood)...and I have tone from the relay's purple wire to the plug (so the wire is good)...but I still cant get this thing fixed....any ideas??:mad2:

Now when I check power at the motor plug I get 0, 9.3v,9.5v,9.6, 0..... and of course nothing works (IE fan or my little 12v brushed motor) at any setting...

 

[atis]

ok... I FINALLY solved it.... the power (hot) wire that is a part of the wiring harness that plugs into the blower switch on the dash had apartently worked itself loose... I noticed it when I went to test it for power (black discolorization) so I cleaned it up and fixed it (apartently it had spread) and plugged it back in... now I dont think that was the initial problem since at one point the only way to get the thing to work was to go inbetween fan speed setting... which is what I think caused the arching that finished damaging it.... but all is well now... :clapping: