2002 2500hd 4x4 8.1l/allison

454ss · December 1, 2005

my headlights go out when i switch from low beam to high beam, somtimes i can make them come on by moving the tilt wheel, if i switch back to low beams everything is ok. i had to replace the multifunction switch in my 1997 k3500 when it started doing funny things like this, but that was at 115,000 miles, this truck only has 50,000. this is not a cheap part and it should last a hell of a lot longer than this. so, is this my problem or do the newer trucks have some other problem area to cause this ? if it is the multifunction switch, is changing it the same as it was on my 1997 k3500, it wasnt too difficult, just a pain in the butt. and what about the air bag, anything i need to worry about when taking the steering wheel off and working inside the column ? THANKS for your help.

GM-Tech · December 1, 2005

Are you sure both high beam bulbs are okay? I've seen more than one tech spend hours trying to diagnose why headlights didn't work only to find out both bulbs were burned out. I know it seems very unlikely that both would go out at the same time. I think what may happen in this caes is that one burns out and it's not noticed, then when the second one goes, it becomes noticeable. In any case, don't overlook this.

We've had some problems with the low beams where the circuit goes through the UBEC (underhood fuse box), though I have not seen this on high beams. The connections overheat and you lose the low beams. It probably doesn't happen to the high beams because they're not in use as much. If you use them a lot, this may happen to them too.

You could go to connect C201 under the dash and ground the high beam circuit directly. This is the honkin' big connector near the bottom of the column, behind the closeout panel under the column. It's a purple wire, cavity E11. The dimmer switch simply supplies a ground to high or low beams, so grounding that pin should turn on the high beams if the dimmer switch is the problem.

454ss · December 1, 2005

i know the bulbs are good because this doesnt happen all the time, and when it does sometimes i can get them to come on by tilting the column. kind of scary at night though when you switch to high beams and all of a sudden have no headlights. if i can get it to do it tonight in the garage i will try grounding the wire as you say, so if this is indeed the problem, how bad is it to change out ? thanks again.

454ss · December 3, 2005

ok, the multifuntion switch is bad, what is involved in chainging it? what do i have to do as far as disconnecting/removing the air bag? thanks

GM-Tech · December 3, 2005

Too bad the pictures don't carry over in a cut and paste. Pull the air bag fuse just to insure you don't blow the thing up in your face. Techs around here almost never pull this fuse (though they should) and I have never seen an airbag go off during a repair, but. someday someone will get hurt.

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Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle

Removal Procedure

Disable the SIR system. Refer to Disabling the SIR System in SIR.

Remove the knee bolster. Refer to Knee Bolster Replacement in Instrument Panel, Gauges and Console.

Loosen the steering column bracket nuts.

Remove the steering wheel. Refer to Steering Wheel Replacement .

Remove the tilt lever from steering column. Refer to Tilt Lever Replacement - On Vehicle .

Important: You must check for 2 pan head tapping screws (1) in the lower trim before removal.

If necessary remove the pan head tapping screws (1) that retain the lower steering column trim cover to the steering column.

If no screws are present, gently unsnap the lower trim cover from the upper trim cover.

Tilt the trim cover down and slide it back in order to disengage the locking tabs.

Remove the lower steering column trim cover.

Slide the shift lever seal up the shift lever.

Important: You must check for 1 TORX head screw (1) in the upper trim cover (2) before removal.

If necessary, remove the screw (1) that retains the upper steering column trim cover to the steering column.

If no screw is present, gently unsnap the upper steering column trim cover.

Remove the upper steering column trim cover. .

Disconnect the steering column bulkhead connector from the vehicle harness.

Disconnect the gray and the black connectors (2) of the switch from the column bulkhead connector.

Disconnect the automatic transmission shift lock control electrical connector.

Remove the wire harness straps from the steering column wire harness (1).

Disconnect the park position switch electrical connection.

Remove the multifunction switch retaining screws from the switch.

Remove the multifunction turn signal/hazard switch.

Installation Procedure

Install the multifunction turn signal/hazard switch to the steering column.

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.

Install the screws retaining the multifunction switch to the steering column.

Tighten

Tighten the screws to 6 N·m (53 lb in).

Connect the park position switch electrical connection.

Install the wire harness straps to the steering column wire harness (1).

Install the gray and black wiring harness connectors (1) to the column bulkhead connector.

Connect the automatic transmission shift lock control electrical connector.

Install the steering column bulkhead connector to the vehicle wire harness.

Tighten

Tighten the center screw to 6 N·m (53 lb in).

Install the wire straps on the steering column wire harness.

Install the steering column trim covers.

Important: If the snap on/off feature on the trim covers was damaged during the removal procedure, you must use screws for the installation procedure.

Install the upper steering column trim cover (2).

If necessary, install the screw that retains the upper steering column trim cover to the steering column.

Tighten

Tighten the upper steering column trim cover retaining screws to 1.5 N·m (13 lb in).

Install the lower steering column trim cover.

Match the tabs slots onto the lower cover with the locking tabs on the upper cover.

Tilt the lower shroud up.

If no screws were present, gently snap the lower trim cover to the upper trim cover.

If necessary, install the screws (1) that retain the lower steering column trim cover to the steering column.

Tighten

Tighten the lower steering column trim cover retaining screws to 3.5 N·m (31 lb in).

Install the tilt lever to the steering column. Refer to Tilt Lever Replacement - On Vehicle .