RamGazer

Strange thing happened on the way home from work this evening. I almost always drive w/ my cruise control on. When I just barley depress the brake to slow down the truck started to accelerate instead of disengaging the cruise. I experimented a couple of times to make sure it wasn't a fluke. Anybody know what might be wrong??

BigIron70

Most likely the brake switch is bad. There are two circuits in switch, one for brake light and another for cruise control. If the switch is not working it will not disengage the cruise, the PCM will try to maintain your speed as you set it by giving more throttle to compensate for you applying your brakes. Don't use your cruise until you replace the switch. You would need to decel at the rate of 10miles per second for the PCM to disengage cruise in emegency if brake switch fails to disengage cruise control.. Or turn the switch off or hit cancel or decel switch on steering wheel..

INSTALLATION
WARNING: To avoid serious or fatal injury on vehicles equipped with airbags, disable the Supplemental Restraint System (SRS) before attempting any steering wheel, steering column, airbag, seat belt tensioner, impact sensor or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the SRS. Failure to take the proper precautions could result in accidental airbag deployment.


CAUTION: The brake lamp switch self-adjusting switch plunger is a one time only feature. If the switch is removed from the mounting bracket, it MUST be replaced with a new switch.




1. Depress and hold the brake pedal in the depressed position.
2. Align the tabs on the brake lamp switch locking collar with the keyed hole in the switch mounting bracket on the lower steering column (1).
3. Insert the tabs on the brake lamp switch locking collar through the keyed hole in the switch mounting bracket until the switch housing (2) is firmly seated against the bracket.
4. Rotate the switch housing counterclockwise about 30 degrees to engage the tabs on the locking collar with the switch mounting bracket.

CAUTION: Release, but do not pull up on the brake pedal before the switch plunger adjustment has been completed.


5. Release the brake pedal, but do not pull it upward.
6. Rotate the plunger adjustment release lever (4) clockwise until it locks into place. The lever should be parallel to the brake lamp switch connector receptacle. This action will set the switch plunger length to a final adjustment position and cannot be undone. If not performed properly the first time, a new brake lamp switch must be installed.
7. Reconnect the wire harness connector (3) to the brake lamp switch.
8. Reconnect the battery negative cable.



BRAKE LAMP SWITCH TESTS
PLUNGER POSITION (2) CONTINUITY BETWEEN
Released (Extended) Pins 1 and 2
Pressed (Compressed) Pins 3 and 4, 5 and 6

RamGazer

Wow!, Thanks for all the info. This is better than my Haynes truck manual.

BigIron70

the switch is resonably priced, at lease the last time I bought one, but follow the install instructions that come with the new switch. Most dealers will not take back a switch that wasn't adjusted right or was installed in vehicle.