2005 Chevrolet Colorado, Blower Only Works On High Speed

This 2005 Chevrolet Colorado came in with the complaint that the blower only works on the high speed. None of the other speeds work. This is a very common problem and easy to fix. It is the same repair on Colorado’s and GMC Canyons. The blower resistor is located under the passenger side of the dash, to the left of the blower motor. To order parts please click here.

A 5.5 mm socket is needed to remove the two mounting screws.

If you look at the back of the connector you can see the change in the wire color caused by heat. Especially the blue wire.

If you double click on the picture below you can see the damage to the two center terminals.

I decided to remove the glove box and pull the wires up to make it easier to work on. I removed the three screws at the bottom edge of the glove box and it came right out. I disconnected the harness from the blower motor and pulled it right up. I did have to remove a harness hold down clip just behind the metal strip at the bottom of the picture below.

I started splicing in the new harness connector and noticed something missing. Do you see the difference between the two plugs?

The green seal is missing from the old connector. This is important in that in this application the seal is there more for shock absorption rather than sealing the connector from moisture.

I staggered the splice joints so that I would have a neat and tidy repair.

Then I taped the harness back up with electrical tape.

When I installed the new resistor and harness connector into the truck, I noticed that the harness hung down slightly and would be easy for someone’s foot to move the harness around.

So I pulled the blower motor vent tube loose and routed the wiring to the top side of the tube and rolled the harness up at the connector. This keeps the wiring as far away as possible from being disturbed. I recommended replacing the blower motor (blower motors drawing too much current have been known to kill the resistors) at this time but the customer declined. I can’t blame them as the motor is working well and the resistors are inexpensive, even if they do fail fairly regular.

If by some chance your blower motor does not work at all and the fuses are good, you may want to take a look at this ground buss bar connection behind the air filter assembly. It may not be bolted down, it may be loose or the connector itself may be burnt out.

A closer look at the ground buss bar connection behind the air filter assembly.

The wiring for the blower systems on these trucks is unusual for GM in that the resistor and the blower switch are on the ground side of the blower motor. The ground originates at the buss bar connector behind the air filter. Goes to the blower switch and is sent to the appropriate blower resistor terminal and then to the ground side of the blower motor. If a ground circuit is missing and the blower motor is good and connected, everything will test as having power on it.