83 El Camino

You didn't take into account the wiper switch is a input to the BCM - body control module ,or do you know that ? The BCM controls wiper one an wiper two relay's to turn on the wipers .
Wondering if it is the PCB or perhaps a physical problem? Guessing never finds the problem . Reading how they work in factory service repair info should be the first step for someone that doesn't know .
Intermittent Operation
Windshield wiper DELAY operation is a low speed wiper motor function with a variable delay interval between the wiper motor cycles. The DELAY interval is determined by a series of 5 resistors within the wiper/washer switch. During DELAY wiper operation, the signal circuit voltage is further reduced through the DELAY resistors. The body control module (BCM) monitors the voltage on the signal circuit to determine the delay interval between the low speed wiper motor cycles.
If the wiper switch is moved from a longer delay interval to a shorter delay interval, the BCM will command an immediate wipe cycle and reset the delay timer to the shorter delay interval.
Additionally, intermittent wiper operation is vehicle speed sensitive. As vehicle speed is increased or decreased, the wiper interval will also increase or decrease.

Low Speed Operation
When the wiper switch is in the Low position, voltage is supplied through an internal resistor to the signal circuit. The body control module (BCM) monitors the windshield wiper switch signal 1 circuit and energizes the wiper 1 relay which will operate the windshield wiper motor. The wiper motor will operate at low speed, since the wiper 2 relay is de-energized. Low speed can also be commanded with a scan tool by commanding Wiper Relay Cmd. ON and OFF.
High Speed Operation
In the High position, the windshield wiper/washer switch supplies voltage to both the wiper 1 and wiper 2 relay coils. This energizes both relays and allows battery voltage from the wiper 1 relay switched output to the switched input of the wiper 2 relay through its contacts and out the switched output of the wiper 2 relay to the high speed circuit of the windshield wiper motor. The windshield wiper motor will operate at high speed. During HIGH speed wiper motor operation, the wiper switch signal circuit is at the LOW speed signal voltage, and the body control module (BCM) supplies redundant voltage to the wiper relay via the wiper diode.

Wiper/Washer System Components
The Wiper/Washer System consists of the following components:
• Windshield wiper/washer switch
• Body control module (BCM)
• Wiper 1 relay
• Wiper 2 relay
• Wiper diode
• Windshield wiper motor
• Windshield washer pump
• Windshield washer nozzles
• Windshield washer solvent container
• Windshield wiper arm and blade assemblies
• Windshield wiper transmission
• WIPER/SW 10A fuse
• WIPER 25A fuse
Refer to Master Electrical Component List.

DTC B3715 02: Front Wiper Relay Drive Circuit Short to Ground
DTC B3715 05: Front Wiper Relay Drive Circuit Short to Battery or Open

Your best bet , take it to a qualified repair shop.

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.

In the under hood fuse box , should have diagram inside the lid . Front wiper's or rear ? Front fuse # 36 - 25 amp. Plus Two relay's PCB hi and Wiper PCB relay . Wouldn't think this being fuse problem . Wiper switch , motor etc... The wiper's are control by a computer . BCM - body control module .

The windshield wiper/washer system consists of front and rear wipers. The front and rear wipers are operative when the vehicle is in accessory or run. The front wipers have 4 different modes: Mist, Intermittent, Low, and High. When the front wipers are in the intermittent mode, there are 5 delay modes to chose from, commanded by the windshield wiper washer switch through the body control module (BCM). The rear wipers has an only one mode.

If the fuse is bad , could have a short to ground or wiper motor pulling to much current (amps) . Fuse's don't just blow for no reason ! Could also have DTC'S - diagnostic trouble codes stored in the BCM .
DTC B3715
DTC B3873
DTC B3875
DTC B3922

DTC B3715 02: Front Wiper Relay Drive Circuit Short to Ground
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 different PCB relays which control the desired wiper speed, high or low.
DTC B3922 00: Front Wiper Function Select Circuit

The PCB relay's are non- servicable , replace fuse box . Soldered in Your best bet mit be to take it to a qualified repair shop .

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 .

not in the bottom of the WASHER FLUID RESERVOIR. It is mounted to the firewall. It is attached to the wiper motor.
Check out the video for blatantly obvious location.
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The intermittent switch has a bad contact in it for the high speed, i would say, most likely will have to replace it.

Would need to scan vehicle to insure the wiper speeds are controlled by the General Module or a wiper intermittent relay....if relay...would locate and replace...if general module.....a reprogram or software update could be in order...possibly replacement.

Scott, Porsche Master Tech 35 years

blower motor might b going bad bearings inside mine did same but when replaced it got all speeds back

i belive that your wiper switch has gone out on the intermittent side. this is a very common problem.
I hope this helps you
Thanks
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I have a 1983 Royal Knight SS. Had the same problem. Had my wiper motor and washer pump replaced. works like a dream now. replaced my original combination turn signal wiper switch on steering column and now have good working intermittent wipers. It is great to see driving in the rain now. Jackson  in ATL