Wiper System/washer System: Other GMC Pickup C2500

FRONT

System uses a permanent magnet, 2-speed, positive-park wiper motor. Motor drives a crank arm, which is attached to individual transmission links for left and right wipers. Wiper motor is sealed and not serviceable (except for delay module on pulse system). Washer pump motor is mounted on fluid reservoir.

System is either a base system or pulse (delay) system. Base system has high and low speeds. Pulse system is similar to base system, but with the addition of a delay function that causes the wipers to sweep once with a delay interval between sweeps. Variable resistor in wiper switch adjusts amount of current to a delay module attached to wiper motor. Delay module controls current to wiper motor.

REAR

In addition to high and low speeds, system has a pulse (delay) feature that causes the wipers to sweep once with a delay interval between sweeps. Variable resistor in wiper switch adjusts amount of current to delay module in wiper motor. Delay module controls current to wiper motor. Wiper motor (including delay module) is sealed and not serviceable.

Note. Ensure ACC-IGN circuit breaker is okay before testing system.

Wipers Inoperative In All Modes

1. Turn ignition switch to ACC or RUN position. Connect test light between ground and White wire terminal of wiper switch connector. (Схема №16) If test light does not come on, repair open in White wire between wiper switch and fuse block.
2. If test light comes on, connect test light between ground and Gray wire terminal of wiper switch connector with wiper switch in LO position, and Light Blue wire terminal with switch in HI position. If test light does not come on at one or both wires, replace wiper switch.
3. If test light comes on at both wires, disconnect wiper motor connector. Connect test light between ground and Gray wire terminal of wiper motor connector with wiper switch in LO position, and Light Blue wire terminal with switch in HI position.
4. If test light does not come on at one or both wires, repair open in Gray or Light Blue wire between wiper motor and wiper switch. If test light comes on at both wires, connect test light from Gray or Light Blue wire terminal to Black wire terminal of wiper motor connector. Turn wiper switch to LO position.
5. If test light comes on, replace wiper motor. If test light does not come on, repair open in Black wire between wiper motor and ground.

Wipers Run At Low Speed Only

1. Turn wiper switch to HI position. Connect test light between ground and Dark Green wire terminal of wiper switch connector. (Схема №16) If test light does not come on, replace wiper switch. If test light comes on, disconnect wiper motor connector.
2. Connect test light between ground and Light Blue wire terminal of wiper motor connector. Move wiper switch to HI position. If test light comes on, replace wiper motor. If test light does not come on, repair open in Light Blue wire between wiper motor and wiper switch.

Wipers Run At High Speed Only

1. Turn wiper switch to LO position. Connect test light between ground and Gray wire terminal of wiper switch connector. (Схема №16) If test light does not come on, replace wiper switch. If test light comes on, disconnect wiper motor connector. Turn wiper switch to LO position.
2. Connect test light between ground and Gray wire terminal of wiper motor connector. If test light comes on, replace wiper motor. If test light does not come on, repair open in Gray wire between wiper motor and wiper switch.

Wiper Motor Runs Continuously Or Will Not Park

1. Turn ignition switch to ACC or RUN position. Turn off wiper switch. Connect test light between ground and Gray wire terminal of wiper motor connector. (Схема №16) If test light comes on, replace wiper switch.
2. If test light does not come on, connect self-powered test light between ground and Black wire terminal of wiper motor connector. If test light comes on, replace wiper motor. If test light does not come on, repair open in Black wire between wiper motor and ground.

Washer Inoperative

1. Turn ignition switch to ACC or RUN position. Turn wiper switch to WASH position. Connect test light between ground and Dark Green wire terminal of wiper switch. (Схема №16) If test light does not come on, replace wiper switch.
2. If test light comes on, disconnect washer pump motor connector. Connect test light between ground and Dark Green wire terminal of washer pump motor connector. If test light does not come on, repair open in Dark Green wire between washer pump motor and wiper switch.
3. If test light comes on, connect test light between Dark Green and Black wire terminals of washer pump motor connector. If test light comes on, replace washer pump motor. If test light does not come on, repair open in Black wire between washer pump motor and ground.

WIPER SWITCH

Note. Manufacturer gives wiper switch removal procedure with steering column removed from vehicle.

WIPER MOTOR

Note. On vehicles with front pulse system, it is not necessary to remove wiper motor to remove delay module.