Grand Cherokee 4WD V8-4.7L VIN N (2000)
Wiper Relay: Testing and Inspection
Wiper High/Low Relay Test
Wiper High/Low Relay
The wiper high/low relay is located in the Power Distribution Center (PDC) between the battery and the fender on the right side of the engine
compartment. See the fuse and relay layout label affixed to the inside surface of the PDC cover for wiper high/low relay identification and location.
1. Remove the wiper high/low relay from the PDC.
2. A relay in the de-energized position should have continuity between terminals 87A and 30, and no continuity between terminals 87 and 30. If OK,
go to Step 3. If not OK, replace the faulty relay.
3. Resistance between terminals 85 and 86 (electromagnet) should be 75 ± 5 ohms. If OK, go to Step 4. If not OK, replace the faulty relay.
4. Connect a battery to terminals 85 and 86. There should now be continuity between terminals 30 and 87, and no continuity between terminals 87A
and 30. If OK, perform the Relay Circuit Test that follows. If not OK, replace the faulty relay.
Relay Circuit Test
1. The relay common feed terminal cavity (30) is connected to the common feed terminal of the wiper on/off relay. When the wiper high/low relay is
de-energized, this terminal connects the wiper on/off relay output circuit to the windshield wiper motor low speed coil. When the wiper high/low
relay is energized, this terminal connects the wiper on/off relay output circuit to the windshield wiper motor high speed coil. There should be
continuity between the cavity for terminal 30 of the wiper high/low relay and the cavity for terminal 30 of the wiper on/off relay at all times. If OK,
go to Step 2. If not OK, repair the open wiper on/off relay output circuit to the common feed terminal cavity for the wiper on/off relay in the PDC
as required.
2. The relay normally closed terminal (87A) is connected to the wiper high/low relay low speed output circuit. There should be continuity between
the cavity for terminal 87A of the wiper high/low relay and the wiper high/low relay low speed output circuit terminal cavity of the windshield
wiper motor connector at all times. If OK, go to Step 3. If not OK, repair the open wiper high/low relay low speed output circuit to the windshield
wiper motor as required.
3. The relay normally open terminal (87) is connected to the wiper high/low relay high speed output circuit. There should be continuity between the
cavity for terminal 87 of the wiper high/low relay and the wiper high/low relay high speed output circuit terminal cavity of the windshield wiper
motor connector at all times. If OK, go to Step 4. If not OK, repair the open wiper high/low relay high speed output circuit to the windshield wiper
motor as required.
4. The coil battery terminal (86) is connected to the wiper high/low relay control circuit. There should be battery voltage at the cavity for terminal 86
of the wiper high/low relay when the ignition switch is in the On or Accessory positions and the wiper switch is in the High position. If OK, go to
Step 5. If not OK, repair the open wiper high/low relay control circuit to the wiper and washer (right multi-function) switch as required.
5. The coil ground terminal (85) is connected to the ground circuit and should be grounded at all times. Check for continuity between the cavity for
terminal 85 of the wiper high/low relay and a good ground. If OK, refer to Wiper On/Off Relay in the Diagnosis and Testing. If not OK, repair the
open ground circuit to ground as required.
