So Fix it

Changing the resistor on the heater blower motor in your Silverado may be necessary if the blower will only run on one speed. When the resistor fails it allows full power to flow from the switch. This results in the fan running either on high speed or not at all, but none of the speeds in-between. Newer Chevy models do not use a traditional resistor; instead they use a controller, but the function is the same.

Instructions

1

Open the passengers side door of your truck and locate the sound insulator on the firewall just above the passenger floorboard. Pull the insulator back to expose the blower motor and HVAC duct under the dash.

2

Locate the controller on the face of the blower motor housing; identifying it by the wiring harness connection running from it to the blower motor. Disconnect the wiring harness connector from the controller and lay it aside.

3

Locate the two retaining bolts on the face of the controller and remove them with a socket and ratchet. Pull the controller off the blower and discard it.

4

Position the new controller on the face of the blower motor, insert the retaining bolts and tighten them with a socket and ratchet. Do not over tighten them or damage may occur to the HVAC housing.

5

Connect the wiring harness connector to the controller, snapping it into place. Push the sound insulator back in place and test the repair by running the fan through all the speeds, verifying it runs in all of them.

When a blower motor resistor fails, the blower motor will only operate in one speed; this is often the first and only sign of a faulty blower motor resistor. This malfunction occurs because the resistor regulates the amount of current flowing to the blower motor in relation to the position of the fan speed control knob. Since the blower motor switch in a 2007 Nissan Versa is located behind the brake pedal assembly, a number of components must be disassembled in order to perform this repair.

Instructions

Removal

1

Shut off the engine and open the hood. Disconnect the negative battery terminal with a metric box-end wrench.

2

Open the drivers side door and remove the fuse panel cover. Remove the screws holding the lower panel finisher with a metric nut driver. Pull the lower panel finisher away from the dashboard until it pops loose. Disconnect the diagnostic data ports electrical connector and remove the finish panel from the vehicle.

3

Disconnect the accelerator pedal position sensors electrical connector. Remove the stop lamp switch from the brake pedal assembly by gently popping it loose.

4

Remove the snap and clevis pins from the brake booster with a small flat-head screwdriver and needle-nose pliers. Remove the nuts holding the brake pedal assembly bracket to the vehicle with a metric socket and a ratchet. Remove the brake pedal assembly from the vehicle.

5

Locate the blower motor resistor. It is situated directly behind the brake pedal assembly on the rear of the firewall. It is held in place by two screws and is rectangular in shape. Disconnect the blower motor resistors electrical connector. Remove the screws holding the blower motor resistor to the vehicle with a screwdriver and remove it from the vehicle.

Installation

6

Set the new blower motor resistor in place and reinstall its retaining screws. Reconnect its electrical connector.

7

Inspect the brake pedal assembly for deformations, bends, cracks, and any sub-standard condition. Measure the lapping length of the sub-bracket and side plate with a metric caliper. Ensure that the length is at least 6.9 mm. If any of these conditions are out of specification, replace the brake pedal assembly before proceeding.

8

Set the brake pedal assembly in place and reinstall the nuts holding the brake pedal assembly to the vehicle with a metric ratchet and socket. Reinstall the snap and clevis pins to their original location.

9

Reinstall the stop lamp switch into the brake pedal assembly. Check the brake pedal assembly to ensure that it operates properly.

10

Set the lower panel finisher into place and press down on it until it snaps into position. Reinstall the lower panel finisher screws. Reconnect the diagnostic data ports electrical connector and reinstall the fuse panel cover.

11

Reconnect the negative battery terminal. Turn on the ignition and test the blower motor to ensure that it operates properly at all speeds.