This 2006 Jeep Grand Cherokee Laredo came in with the complaint that the blower will only work on high speed. The blower resistor is located behind the glove box area.
I started by removing the two 7 mm screws that attached the lower hush panel to the bottom of the dash.
With the two screws removed, the panel unsnaps from the center and then is pulled out the passenger side of the vehicle.
Then the glove box is opened and the two upper bump stops are pulled down to drop the glove box even further.
With the glove box fully opened the glove box can be lifted slightly and the lower corners of the glove box have to be bumped up to release the hinges from the hinge pins.
The hinge pin.
The hinge hook at the bottom of the glove box.
Now we can see the blower resistor and related wiring.
After unplugging the harness connector from the blower resistor the main problem was quite evident. The damage to the terminal of the blower resistor is harder to see but there none the less.
I used this set up to test for switched ground at the resistor connector.
I used the bleed through power from the blower motor on the light blue wire. I then touched the tip of my test light to the remaining three terminals individually as the blower switch was rotated through the speeds. The ignition switch was of course on during this test. The blower switch circuits tested as okay. Keep in mind that this was an unloaded test and does not guarantee the blower switch will supply the needed amperage to work the blower motor.
Time to start splicing in the new harness connector. I disconnected the fresh air door actuator wiring. Slid the blower motor harness connector off of its retainer and pulled the wire tie clip from the box. Then I had to remove the wire tie hold down and strip the tape from the harness.
Now that the harness is opened up, you can see that the light blue wire, that supplies switched ground control to the blower motor has a splice in it. When the high blower position is selected at the switch the switch sends a direct and full ground to the blower motor. In all other speed positions, the switched ground is sent from the blower switch to the resistor on the remaining three wires. Depending on which speed is selected, the ground signal is sent through one of the three internal blower resistors. That signal goes out on the light blue wire at the resistor harness connector and over to the blower motor. Thus controlling the blower motor speed.
I started by cutting out the old splice connection and installing a new splicing connector and heat shrink tubing.
I heated the tubing and shrank it into place.
I then continued to cut and splice the remaining three wires. Notice that I staggered the splice joints.
Then taped the wires back into a harness assembly.
I then connected all of the harness ends and secured in place. The kit I used has a new wire tie to replace the one that I had to cut off. If you would like to purchase one of these kits, please click here.
I made sure every thing was laying properly in place and then pulled the wire tie tight.
All of the wiring repaired and back in place with a new blower resistor.
All blower speeds now worked.