Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
The STOP LP fuse in the engine wiring harness junction block supplies battery positive voltage to the normally open stop lamp switch. When the driver presses the brake pedal, the switch contacts close and battery positive voltage is supplied to both the VECHMSL fuse and the TRCHMSL fuse. On the pickup only, voltage is also supplied to the CHMSL relay in the underhood fuse block which energizes the relay. The energized CHMSL relay supplies battery positive voltage to the multifunction turn signal switch. The utility is not equipped with the CHMSL relay therefore battery positive voltage to the multifunction turn signal switch is supplied directly from the from the stop lamp switch. The current flow from the multifunction turn signal switch continues to the stop lamps which are grounded at G475 and G422 on the pickup and G450 on the utility. The center high mounted stop lamp (CHMSL) is grounded at G202 on the pickup and G450 on the utility.
I am sending a schematic to help you.Check for voltage at the base of the steering column electrical connector.
(CKT 1850) Body harness, to the LF of the I/P, above P100
I/P bulkhead pass-through, LR of the engine compartment, on the cowl
(CKT 1350) Body harness, in the LR body corner, near C403 to the tail lamp harness
The steering wheel & air bag do not need to come off.Yes,the stop lamps use the green wire leaving the switch.Here is some info to help you.
Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle
Caution: This vehicle is equipped with a Supplemental Inflatable Restraint (SIR) System. Failure to follow the correct procedure could cause the following conditions:
Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Tighten Tighten the multifunction, turn signal, and hazard switch retaining screws to 6 N·m (53 lb in).
Tighten Tighten the steering column bracket nuts to 30 N·m (22 lb ft).