NEED HELP Blower not engaging at any speed.

[Chugs]

Hello, I've been chasing a problem with my 03 TB blower not working. I'm at a loss I am not getting signal from a ATC to my blower control module.all the HVAC and fan fuses are good and so are the relays. I've tested my blower motor and it still runs. I've tested the module and it did not work I replaced it with a new one. Since I replaced that I stopped getting signal from the controls on the purple/white wire. I still have 12v and the ground and if I jump power to the purple/white signal wire the fan will blow. So I picked up a new ATC and replaced that and still no blower. I'm at my wit's end and am not sure what else it might be. Does anyone have some advice?

 

[Mooseman]

I assume you have an auto HVAC system? How are you measuring this signal? I can't remember anyone mentioning what that signal is. Or are you talking about the power wire from the module to the blower? Have you tried resetting the system by pulling the HVAC-B fuse under the seat? What brand module did you use?

 

[Chugs]

I have tried resetting the system. I used a Borg Warner module. And there is a purple and white wire that runs from the ATC to the blower control module that is supposed to send varied voltage depending on the speed selected on the ATC. Signaling the module to supply the blower with power.

 

[Mooseman]

Auto or manual HVAC? First I've heard of BWD making these blower modules. Usuals are ACDelco and Dorman. If you have a link to the module you used, that could be helpful.

 

[Chugs]

The BWD part number is RU1321.and I have automatic temperature controls.
BWD 5 Blade Blower Motor Resistor RU1321 | O'Reilly ...
https://www.oreillyauto.com › bwd-3123

 

[Mooseman]

What was it doing prior to replacement? What led you to the module needing replacement? Did you replace the connectors/wiring with the ones that came with the module? There was something changed with the wiring requiring the wiring to be replaced.

 

[Chugs]

I lost my fan high speeds then all my speeds completely.i replaced the pigtail with the one provided by bwd as it was an upgraded connector.

 

[budwich]

but you need to check the wiring replacement as I don't believe that it is obvious in terms of the "wire to wire" connection. There have been threads posted with similar problems.

 

[Chugs]

It was just 3 wires to splice. red 12v black ground and purple signal.

 

[budwich]

You might want to "rethink" that ^....
maybe post a picture of what you did. Iirc, there are possibly 5 wires involved... could be wrong but as I mentioned people have found wiring "fubars" going away from the OEM setup to something else.

 

[Chugs]

You might want to "rethink" that ^....
maybe post a picture of what you did. Iirc, there are possibly 5 wires involved... could be wrong but as I mentioned people have found wiring "fubars" going away from the OEM setup to something else.

Yes your correct there are 5. 2 go to th blower and already had its pigtail attached. If I jump power over I can get the blower to

 

[budwich]

Ha... BUTTT when you are "jumping" the two wires to the motor, you aren't jumping them "thru" the controller. So you are making an "assumption" that the two wires that plug into the the "motor connector" are the two wires that indeed come out "correctly" from the controller.... remember what I said about "wiring fubars"... what I and others don't necessarily know that the "5 pin connector" is actually wired correctly so that indeed those two wires are the RIGHT two wires that need to go to the motor.

You likely need to doubt check with a meter when the plug is connected to the controller, what you are seeing.... the best check would be for grounds (resistance check... key off) go from there. My guess is you have the wrong wire for the "motor control signal"... IF I read the schematic correctly and the color codes that the manufacturer used / provided mean anything.

Looking further... definitely check the ground connection.

 

[Chugs]

The purple wire would carry viable voltage on this one wire from the ATC through the relay and to the control module. If I jump 12v to the purple wire through the module it turns the fan on high. I have unhooked the relay and tested it, and the relay is functional.

 

[budwich]

ok... how about this

https://gmtnation.com/forums/thread...dule-problem-blower-motor-wont-turn-off.1407/

Further, I just re-read your first post... missed the point about the replacement of the ATC module as oppose to the blower speed control motor.... sorry.
There are TWO powering "sources" going to the atc... have you check BOTH fuses? Have checked the powering at the atc module?