Rear blower inop
 

I have a 2004 Suburban with automatic a/c controls. The rear blower is not working. I checked for power and ground at the blower, and had neither. I replaced the blower motor control module with the new updated model. It is still inop, so I checked the wires at the module and realized I had power ground, but no reference voltage on the purple wire. I borrowed a Modus scan tool from the Snap On dealer and and was able to read inputs for the the blower control from both the overhead controls and aux controls, so that pointed to a bad HVAC control module-auxillary. I changed out the module and still have no reference voltage coming to the blower control module to turn it on! I Ohmed out the purple (ref voltage) wire from the blower control module to the HVAC control module and it is good! I have supplied power and ground directly to the rear blower, and it works. I'm starting to feel lost and am not sure what the check next.

My 2004 surburban does the EXACT same thing! All my checks are EXACTLY the same!! What did you do to fix it??!!??

I found out that using a multi-meter to check for power at the blower control module was giving me a false voltage.....it showed 12+ volts, but when I put my test light on it, it would not light up. So make sure you really have enought juice on the main power wire to the blower control module to light your test light. If not, you should find a burnt wire at the connector behind the kick panel at the parking brake. I just cut the wire at both sides of the connector, and spliced them back together.

Is this old or did you fix your problem

Not sure if this are old post or current issues but I just fixed mine and if you need info let me know. Maybe I can help.

Mine works sometimes and sometimes it doesn't. What did you do to fix it Helpu?

Looks like u are on the right track. Was it the FSR module for the Rear AC blower you replaced or was it the Rear AC overhead Control Module above the front seats you replaced?
I am assuming that your rear AC blower runs normal if you jumpered the power(12vdc) wires at the FSR, correct?

Do not waste your money on the Online mechanic as I did. They did not seem to understand the troubleshooting I did just like u and I ended up being very frustrated and pieced together info from other posts to fix mine. Here's my email in case we get lost: filsua@yahoo.com

Take a pic of your FSR and indicate input power wire color(from the battery or fuse) and the output(to the blower) wire color as the non EOM FSR have different color wires---it was on my 2000 Sub. Also indicate the GND wire color and the sensor wire. A pic of the wires connected to unit(normal) is better

Hello rtkachuk. Not sure if I replied to your question already. Tell me what you have done/troubleshoot so far and your mech/auto elect savviness