Climate control fan switch

Lose connections , Switch , BCM - body control module , wiper control relays . wiper motor going bad etc.... Taking the vehicle to a qualified repair shop to have it diagnosed would be your best bet . Could have DTC'S - diagnostic trouble codes stored in the BCM . There is nothing commom about these systems .

The windshield wiper/washer switch signal circuits are inputs to the body control module (BCM) and the BCM controls wiper motor low speed operation, washer pump and high speed operation. The windshield wiper/washer switch is provided a low reference from the BCM and each of the switch signal circuits is supplied 12 volts through a resistor and monitored within the BCM. During LOW or INTERMITTENT operation the wiper switch low signal circuit is closed to the low reference circuit through a series of resistors within the switch assembly and the signal circuit voltage monitored by the BCM will depend on the switch contact location to the resistor assembly. During HIGH or WASH operation the high and wash switch signal circuits are closed directly to the low reference circuit within the switch assembly and nearly all the signal circuit voltage will be dropped across the BCM resistors. The BCM controls the wiper motor through the WIPER CONTROL PCB Relay and the WIPER SPEED PCB Relay. During any wiper motor function that uses low speed the BCM supplies the voltage to energize the WIPER CONTROL PCB Relay and battery voltage will be supplied from the WIPER CONTROL PCB Relay through the de-energized WIPER SPEED PCB Relay to the wiper motor low speed control circuit. During high speed wiper motor operation the WIPER CONTROL PCB Relay is energized as in low speed and the BCM provides a ground to energize the WIPER SPEED PCB Relay and the battery voltage is supplied to the wiper motor high speed control circuit. Wiper motor park operation is controlled by the BCM using an input from the park switch within the wiper motor assembly. The BCM supplies the park switch signal circuit 12 volts through a resistor then monitors the circuit. Whenever the wiper motor is out of the park position the park switch signal circuit is closed to ground and nearly all the signal circuit voltage will be dropped across the BCM resistor. When the wiper switch is turned to the OFF position while the wiper motor is somewhere in mid-cycle, the BCM will continue to operate the motor until the wipers reach the park position. If the ignition is turned OFF while the wipers are in mid-cycle, the wipers will stop immediately where they are and the BCM will park the wipers the next time the ignition is cycled ON.

DTC B3715 02: Front Wiper Relay Drive Circuit Short to Ground
DTC B3922 00: Front Wiper Function Select Circuit

Yukon what ? just a plain yukon ? 2WD or 4WD XL - Denali etc...
No pulse board . controlled by the BCM - body control module . Taking the vehicle to a qualified repair would be your best bet .
Windshield Wipers
The windshield wiper/washer switch signal circuits are inputs to the body control module (BCM) and the BCM controls wiper motor low speed operation, washer pump and high speed operation. The windshield wiper/washer switch is provided a low reference from the BCM and each of the switch signal circuits is supplied 12 volts through a resistor and monitored within the BCM. During LOW or INTERMITTENT operation the wiper switch low signal circuit is closed to the low reference circuit through a series of resistors within the switch assembly and the signal circuit voltage monitored by the BCM will depend on the switch contact location to the resistor assembly. During HIGH or WASH operation the high and wash switch signal circuits are closed directly to the low reference circuit within the switch assembly and nearly all the signal circuit voltage will be dropped across the BCM resistors. The BCM controls the wiper motor through the Wiper Relay and the Wiper High Relay. During any wiper motor function that uses low speed the BCM supplies the voltage to energize the Wiper Relay and battery voltage will be supplied from the Wiper Relay through the de-energized Wiper High Relay to the wiper motor low speed control circuit. During high speed wiper motor operation the Wiper Relay is energized as in low speed and the BCM provides a ground to energize the Wiper High Relay and the battery voltage is supplied to the wiper motor high speed control circuit. Wiper motor park operation is controlled by the BCM using an input from the park switch within the wiper motor assembly. The BCM supplies the park switch signal circuit 12 volts through a resistor then monitors the circuit. Whenever the wiper motor is out of the park position the park switch signal circuit is closed to ground and nearly all the signal circuit voltage will be dropped across the BCM resistor. When the wiper switch is turned to the OFF position while the wiper motor is somewhere in mid-cycle, the BCM will continue to operate the motor until the wipers reach the park position. If the ignition is turned OFF while the wipers are in mid-cycle, the wipers will stop immediately where they are and the BCM will park the wipers the next time the ignition is cycled ON.

The PCB wiper relays are soldered directly to circuit board inside the under hood fuse box.
The windshield wiper/washer switch signal circuits are inputs to the body control module (BCM) and the BCM controls wiper motor low speed operation, washer pump and high speed operation. The windshield wiper/washer switch is provided a low reference from the BCM and each of the switch signal circuits is supplied 12 volts through a resistor and monitored within the BCM. During LOW or INTERMITTENT operation the wiper switch low signal circuit is closed to the low reference circuit through a series of resistors within the switch assembly and the signal circuit voltage monitored by the BCM will depend on the switch contact location to the resistor assembly. During HIGH or WASH operation the high and wash switch signal circuits are closed directly to the low reference circuit within the switch assembly and nearly all the signal circuit voltage will be dropped across the BCM resistors. The BCM controls the wiper motor through the WIPER CONTROL PCB Relay and the WIPER SPEED PCB Relay. During any wiper motor function that uses low speed the BCM supplies the voltage to energize the WIPER CONTROL PCB Relay and battery voltage will be supplied from the WIPER CONTROL PCB Relay through the de-energized WIPER SPEED PCB Relay to the wiper motor low speed control circuit. During high speed wiper motor operation the WIPER CONTROL PCB Relay is energized as in low speed and the BCM provides a ground to energize the WIPER SPEED PCB Relay and the battery voltage is supplied to the wiper motor high speed control circuit. Wiper motor park operation is controlled by the BCM using an input from the park switch within the wiper motor assembly. The BCM supplies the park switch signal circuit 12 volts through a resistor then monitors the circuit. Whenever the wiper motor is out of the park position the park switch signal circuit is closed to ground and nearly all the signal circuit voltage will be dropped across the BCM resistor. When the wiper switch is turned to the OFF position while the wiper motor is somewhere in mid-cycle, the BCM will continue to operate the motor until the wipers reach the park position. If the ignition is turned OFF while the wipers are in mid-cycle, the wipers will stop immediately where they are and the BCM will park the wipers the next time the ignition is cycled ON.

DTC B3715 02: Front Wiper Relay Drive Circuit Short to Ground
DTC B3875 00: Wiper High Speed Relay Circuit
DTC B3922 00: Front Wiper Function Select Circuit
Have it checked for DTC'S - diagnostic trouble codes .

The body control module (BCM) controls the wiper motor based on input from the windshield wiper washer switch. The BCM monitors the wiper washer switch through three separate signal circuits and a ground circuit. The windshield wiper switch high signal circuit is used to determine high speed wiper operation, the windshield wiper switch low signal is used to determine low speed, intermittent, and mist operation through the use of a resistor ladder, and windshield washer switch signal circuit is used to determine washer operation.
The BCM controls the windshield wiper motor through two output controls, controlling two relays which determine the desired wiper speed, high or low.
Your best bet , take your vehicle to a qualified repair shop or dealer . Hooking up a factory scan tool to see what the wiper switch inputs to the BCM are correct and outputs to relays are good .

Looks like you are not alone in this. Take a look at this video that may help solve your issues. Good luck DIY How to Replace Heater AC Blower Motor on Chevy Blazer GMC Jimmy S10...

It could be Clutches and Bands. Do you have over-sized Tires and Wheels?

Sounds like your controller is bad. http://www.resistorguide.com/applications/blower-resistor/ <Read this info.
http://www.ebay.com/itm/88-94-GMC-CHEVY-TRUCK-CLIMATE-HEATER-CONTROL-93-92-max-SILVERADO-SUBURBAN-SIERRA-/381127684906

did you check the climate control module,check first if you are getting power to the blower motor and go from there.










TIM............

Hello,
I suggest checking the fuses. If the fuses are ok it may have a bad module or switch unit.
I hope this helps.
Roy

hi how are you doing? just had same problem with by gmc i replaced the transfurcase motor and it works fine. the electric motor moves the shifter in your transfurcase from 4hi to 4lo and 2hi.there is only 3 things that operate your 4x4 the switch the motor and the control modgual.

Call your local GMC Dealer and see if they have the climate control panel in stock. What happens is the circuit board on the back of the panel shorts out. The panel comes as an assembly and is very easy to replace. Don't go with a wrecking yard piece. I made that mistake once and it didn't work either. I got one from the Chevy dealer and it worked perfectly.