Three wires from Blower motor, Two wires on replacement blower
 

I have a weird problem. I have a computer climate controlled system. I actually had three connectors on the blower motor. I had the standard 2 prong connector ( it is different from the manual controlled system, and this thing had a third prong outside the connector. I have found out it is not a ground. The replacement units don't have a connector for this, and the AC/Delco unit has a pin like it on the outer part of the motor that is a ground. I have tried grounding this wire, and should have tested it first for voltage. It appears to have 12 V going though it. I suspect its a speed sensor.

The problem is that the original motor allowed the computer climate control to set the actuator for floor, defrost, front vents or any combination. With this cable disconnected due to no connector, the floor vents no longer work individually. I can do floor in combination with defrost or front vents, but the computer won't put it in floor only. When I connected this wire to ground, it killed the motor, and now my trip odometer rests every time I start the truck. I suspect I burned something up.

In any case, what is this wire and where the heck do I find the right motor.

Thank You ,

-Max

Glad this got resolved.. nice job group

Hi Max,

Ok, This is weird. I don't recall that when I replaced my blower motor for my system with the Auto Temp Control that I was no longer able to put it in heat mode only (i.e. only floor vents open). Am I reading what you wrote incorrectly?

According to the attached the schematic, the brown wire, the third one, connects to a resistive sensor of some sort. I can only assume it is for reading temperature based on all of the other schematics that label such a symbol (variable resistor in a box) as a "temperature sensor." But there are other sensors in the cabin vents for measuring temperature of the air blowing out so I don't know what this one might be for except to sense an overheating condition in the motor for the solid state control module? At the moment, with my brown wire disconnected, it is seeing in infinite load/resistance = no current input to/from the control module. If it is a thermistor, as is what appear to be used for the other temp sensors, then when it is cold, the resistance is greatest so that with the wire disconnected, the control module will think that the motor is cold and not overheating.

BTW, I found the blower motor I used as a replacement is the Four Season 35139. I got it from Rock Auto and they still have them.

BravadaJunk, please try to stay in the present if you wish to reply to other members' requests where your assistance can be offered, received, and actually used. There is not much point in replying to threads that were obviously missed years ago, especially if you are going to do so in such a manner as to only browbeat those that were here at the time which serves no purpose at all. Thank you.

Christine, I'm going to close this thread as the OP hasn't been on since 2015 so I'm not sure if they'll ever read your reply. If they do log back in, I hope they'll post a new thread.