This 1998 Chevrolet C1500 came in with a no blower complaint. The starting place for testing is at the blower motor. The blower motor is located behind the passenger side of the dash and is accessed by removing the glove box.
After opening the glove box there are two retainers that have to be dealt with. The one on the left is a plastic cable. To release it, lift the locking tab, lift the door slightly and pull the cable towards you.
The second retainer is a bump stop and to release it, flex the glove box housing inward as shown below.
After both retainers are released, lower the glove box down and rotate it off of its hinge pins.
Locate the purple wire at the blower motor, switch the ignition on and set the blower switch to the high position. I had power (red glow at my finger tips) which told me that the basic controls were working on the power side.
Next I checked for power on the black ground wire. That’s right, I checked for power on the ground wire. If I would have seen power on the black wire it would indicate that the power coming in on the purple wire was going all of the way through the motor windings and brushes and that there was no ground being supplied to the black wire.
To further confirm that the ground was okay, I placed a jumper wire into the purple wire, connected my test light clamp to the jumper wire. Then, I touched the black wire and my test light lit up indicating that both power and ground are present. With the wires reconnected to the blower motor, I bumped the back of the blower motor with the palm of may hand. This will sometimes reset worn brushes in a faulty blower motor to further confirm the test results.
To remove the cover over the blower motor the wires of course have to be disconnected. Then you have to release the upper and lower retainers. At the top, the cover has a slot in it that hooks over a flat pin. Lift up on the rear edge and lift the cover off of the flat pin.
At the bottom there is a round pin and there is a stepped notch in the cover. You have to push the cover towards the firewall and then pull the cover off of the lower pin.
After both retainers are released, the cover can be pulled down in stages as you flex it and move it around. It will catch in different places.
Finally you can see the blower motor.
The lower screws are easy to remove. The two upper screws are a little more difficult and you will need a swivel to remove them.
Once the screws are out the blower motor will come out. Pull it out until it it full loose of then housing then rotate the motor until the flat edge is pointing up. Roll the motor down and out. The fan blade will need to be flexed also.
The new motor on the left and the old on on the right.
The new motor does not come with the ground terminal attached, so the old one has to be removed and attached to the new motor. Note the position of the terminal.
Now, the paint has to be removed from the new motor where the ground terminal attaches. A pocket knife works well for this. Install the ground terminal in the same position as it was in on the old motor. If you do not the cover will not line up correctly. Tighten the attaching screw. Do not over tighten and strip the metal out. Do not leave loose as heat will build up and burn the terminal.
The new motor also does not come withe the mounting ferrules or tubes either, so they also need to be transferred.
The fan blade or impeller has to be flexed slightly to place the motor back into the housing. The motor can only be installed one way that will allow the vent tube to be properly attached. I actually prefer using the old vent hose if it is in good shape. It makes the cover installation easier.
It is aggravating, but to put the cover back into place, it will have to be worked on in stages
I had noticed that my jumper wire was a little loose in the terminal on the purple wire so I tightened the spring tension of the terminal as shown below.
If I would have had no power at the purple wire I would have gone to the blower relay and resistor at the left side of the glove box opening to do more testing.
To see more testing related to the relay and resistor please click here.