Sorry for the delay, my internet has been acting up today. Is this the part you have replaced in the rear?
Also if you check at blower plug the voltage should be 12volts on high speed and decrease down from there on the lower speeds, I cant access my info at the moment but see what your readings are from low to high at the motor connector unplugged. Thanks, Eric
Lets run back through from the beginning and see what were missing. Here is a diag chart for your problem. Do you have a scan tool able to get into body functions?
1. Access the rear blower motor, behind the Right Rear (RR) wheel, inside of the vehicle. 2. Test for constant B+ to the blower motor on the Orange wire. 3. Test for a constant ground to the blower motor on the Black wire. 4. Test voltage on the Purple wire at the blower motor. 5. Should have 0.4 to 4.0 volts as the blower control is moved from low to high speed. 6. Check Heat Vent Air Conditioning (HVAC) auxiliary blower data with a scan tool. 7. The blower command should change from 0 to 98% as the blower speed control switch is moved from off to high. 8. Check for HVAC auxiliary blower related codes with a capable scan tool.
I still think my problem has to do with the Purple wire (Ignition 3 Voltage Circuit) not registering enough voltage to power a simple test lamp (6v-12v).
I followed the test descriptions you sent. Here are my process responses.
Step 1. Reviewed auxiliary HVAC operation and moved to Step 2
Step 2. Performed auxiliary blower functions but does NOT operate at any speed setting of the front and rear blower motor switches.. Got to Step 3
Step 3. Disconnected Auxiliary blower motor, turn ignition ON with engine off, connected a test lamp (and Volt meter) between the auxiliary blower motor supply circuit (Red wire from blower motor resister module) and a good ground and Test Lamp did not illuminate (voltmeter read 00.4V)... go to step 6.
Step 6. Disconnected the auxiliary blower "motor resister" assembly connectors, probed Ignition 3 voltage circuit (Purple wire) with test lamp connected to a good ground. Test lamp DID NOT illuminate. However, It did illuminate when I probed the Battery Positive voltage circuit (Orange wire). Go to step 15.
Step 15. Repair the ignition 3 voltage circuit of the auxiliary blower motor resistor assembly. Need to refer to "Wiring Repairs" in wiring systems but the referenced Hyper Link does not work. Can you provide Wiring Repairs instructions? Thanks. Also will need Test Description Steps 21 and beyond. Thanks.
Not certain what you mean (Jump power from orange wire to the purple wire)? I have used alligator clips from Orange wire direct to motor positive connector and good ground and the motor did operate.
Do you mean for me to use the orange wire in place of the purple wire directly into the Motor Resistor Module?
Cam, you have more faith in my ability than I do. I have always steered clear of Electrical Repairs. I am more your Pull and Replace component type of DIY mechanic. BUT... I'll give it a try. Hopefully, the wire coming out of the RBEC is also purple, and with any luck, is getting good voltage from left dash fuse block. If I do this, should I also consider splicing in a FUSE along the path? and what size fuse should I use?
Thanks for your help Cam.
Brown wire, corner pin, b1. That's very helpful.... Thanks!
Done for the night. 9:10pm local.
Rear switch brown wire, at connector, does not have 2 wires to 1. Traced brown wire back to mid-harness and located a brown 2 to 1 at that location. Registered no Volts with key in on position.
I'm becoming convinced that it is the rear controller Part number 1572860. I have been able to make the rear blower motor operate by bypassing at mid-harness (alligator clips) from purple wire to light blue wire and also purple wire to red wire. Also able to get rear blower motor to operate from rear switch connector (again alligator clips) where corresponding purple wire, light blue, and red wires go in. I get nothing if I plug rear switch connector harness (21 pin) into rear controller.
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your images are not showing up on my end. can you send as PDF.
if you're convinced... I'll try to follow the brown wire back to the corner pin, b1 tomorrow but I am not certain what I'm looking for when I look at the RBEC. Perhaps that's the photo you are trying to send. Thanks for your help.
I have my Suburban interior all disassembled on the inside anyway...
Thanks for the images... wish I was better at reading Auto Electrical Schematics. :-( I'll dwell on these tomorrow and see what I can accomplish. Thanks for saving the cost of yet another part from Rock Auto. They're making a killing off of me.