99 Astro Van front blower motor not working

[fquan]

After four months, I finally have the time to do some troubleshooting. The blower motor was replaced in February this year. The blower worked on low, med 1 and med 2 for a few weeks and then stopped working completely. Not sure if I need to replace the blower motor again but if I do, it has a lifetime warranty.

Just in case it was something else, I followed OM's instructions on testing voltage. I used my multimeter, stuck the positive probe into each connector slot as instructed, grounded the black probe, set the blower switch positions and each position showed 12.13 volts. The black wire showed 1 ohm.

So my question is, is my blower motor bad or is it my harness and resistor. Looking at the connector harness, I noticed the far left part of the connector is burned out and apparently it was fixed in the past with a female spade terminal. Am I headed in the right direction? So, is it the blower motor or resistor. Thoughts? Thanks in advance.

Originally Posted by old_master

Turn the ignition to the RUN position.
Select HEAT on the HVAC mode switch.
Unplug the blower resistor/relay pack connector on the front of the evaporator housing, next to the AC accumulator, (large aluminum "can").
At the electrical connector check the following:
Yellow wire must show battery voltage with blower switch in the LOW position.
Tan wire must show battery voltage with blower switch in the MED 1 position.
Light blue wire must show battery voltage with blower switch in the MED 2 position.
Orange wire must show battery voltage with blower switch in the HIGH position.
Red wire must show battery voltage at all times.
Black wire must show less than 5 ohms resistance to ground at all times.
Purple wire goes to the blower motor.

Post your results for each wire.

[fquan]

Since I was getting electricity out of the connector harness and there was electricity going to the blower motor, decided to buy a resistor and that did the trick. After I was done with that, I replaced the broken vacuum hose that causes the air to come out of the defrost vents. A new vacuum hose cost less than $2 for a 3 foot section. That was a pain but now everything works nicely.

[gmtech1]

Glad to hear you got it fixed! Thanks for posting the repairs!

[fquan]

Forgot to mention that to get to the connector on the manifold, I removed the doghouse. As you look at the driver's side of the engine from inside the van, you'll see the PCV and about 2-3 inches behind it, you'll find the connector for the vacuum hose. Taking off the doghouse and reattaching it took the most time. Attaching the hose was easy.

[fquan]

Arghhh....low and med 1 just died on me. Med 2 and high blow just fine. No doubt the resistor is causing the problem. I'll head over to AZ and get a new one since the one I bought has a lifetime warranty. Whew! Anyone have any thoughts on what might have caused this problem? Dirty connectors? Bad grounding?

[fquan]

Just replaced the resistor with a new one and the low and med 1 works just fine. I'll see how long the different speeds work before they die out.