Wiper repair for 2002 GMC Envoy . it only works on high speed. how do i fix it

Do you know how to test electrical circuits ? Probably the wiper motor cover needs to be replaced .
1
Did you perform the Wiper/Washer System Diagnostic System Check?
--
YES - Go to Step 2
NO - Go to Diagnostic System Check - Wiper/Washer
2
Turn the ignition ON.
Attempt to operate the windshield wipers in all modes.
Does the system operate normally?
--
YES - Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
NO - Go to Step 3
3
Do the windshield wipers operate in the high speed mode?
--
YES --- Go to Step 5
NO - Go to Step 4
4
Disconnect the steering column harness connector.
Connect a fused jumper wire from the windshield wiper switch high signal circuit terminal in the body harness connector half to a good ground.
Turn the ignition ON.
Do the windshield wipers operate at high speed?
--
YES - Go to Step 8
NO - Go to Step 7
5
Disconnect the windshield wiper motor connector.
Test the resistance from the windshield wiper switch voltage supply circuit terminal to the windshield wiper switch signal 1 circuit terminal in the windshield wiper motor harness connector.
Operate the windshield wiper/washer switch in the following positions:
• MIST
• LO
Is the resistance near the specified value in the listed switch positions?
380 ohms
YES - Go to Step 6
NO - Go to Step 10

6
Test the resistance from the windshield wiper switch voltage supply circuit terminal to the windshield wiper switch signal 1 circuit terminal in the windshield wiper motor harness connector.
Operate the windshield wiper/washer switch in all of the delay positions.
Does the resistance remain within the specified values from low to high as the delay speed is increased?
1000 ohms-10K ohms
YES - Go to Step 14
NO - Go to Step 12
7
Test the windshield wiper switch high signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
YES - Go to Step 16
NO - Go to Step 14
8
Test the wiper switch ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
YES - Go to Step 16
NO - Go to Step 9
9
Test the windshield wiper switch high signal and ground circuits in the steering column harness for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
YES - Go to Step 16
NO - Go to Step 12
10
Test the windshield wiper switch voltage supply circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
YES - Go to Step 16
NO - Go to Step 11

11
Test the windshield wiper switch signal 1 circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
YES - Go to Step 16
NO - Go to Step 12
12
Inspect for poor connections at the windshield wiper/washer switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
--
YES - Go to Step 16
NO - Go to Step 13
13
Replace the windshield wiper/washer switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement in Steering Wheel and Column.
YES - Did you complete the replacement?
--
NO - Go to Step 16
--
14
Inspect for poor connections at the windshield wiper motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
--
YES - Go to Step 16
NO - Go to Step 15
15
Replace the windshield wiper motor cover. Refer to Wiper Motor Cover Replacement .
YES - Did you complete the replacement?
--
NO - Go to Step 16
--
16
Operate the system in order to verify the repair.
Did you correct the condition?
--
YES - System OK
NO - Go to Step 3


Wiper Motor Switch Troubleshooting

Switch is bad.