Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests for a faulty tow/haul switch.
- 3: This step tests for voltage input from the BCM to the tow/haul switch.
- 6: This step tests for ground integrity.
Tow/Haul Switch/Indicator Always On or Inoperative
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| 1 |
|
- | Go to Intermittent Conditions in Engine Controls - 6.0L | Go to Step 2 |
| 2 |
|
- | Go to Step 7 | Go to Step 3 |
| 3 | Using the DMM and the J 35616
, measure the voltage at the low reference of the tow/haul switch connector.Special Tools
. Is ignition voltage measured? |
- | Go to Step 6 | Go to Step 4 |
| 4 | Using the DMM and the J 35616
, measure the voltage at the tow/haul switch signal circuit of the body control module (BCM).Special Tools
. Is ignition voltage measured? |
- | Go to Step 5 | Go to Step 8 |
| 5 | Test the Tow/Haul switch signal circuit of the tow/haul switch for an open or shorted condition. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 9 | Go to Intermittent Conditions in Engine Controls - 6.0L |
| 6 | Test the ground circuit of the tow/haul switch for an open or shorted condition. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 9 | Go to Intermittent Conditions in Engine Controls - 6.0L |
| 7 | Replace the tow/haul switch. Refer to Shift Lever Replacement (With Tow/Haul Switch)
or Shift Lever Replacement (Without Tow/Haul Switch)
in Steering Wheel and Column. Did you complete the replacement? |
- | Go to Step 9 | - |
| 8 | Test the BCM for proper operation. Refer to Diagnostic Starting Point - Computer/Integrating Systems
in Computer/Integrating Systems. Did you find and correct the condition? |
- | Go to Step 9 | - |
| 9 | After the repair is complete, observe Tow/Haul Mode on the scan tool display, while cycling the tow/haul switch. Does the scan tool display Active when the switch is first pressed, and then Inactive when the switch is pressed again? |
- | System OK | Go to Step 1 |