QuestionPT Cruiser 04 Turbo 84,000 miles. ABS, TRAC OFF, lights are on all the time Don't have these units in vehicle. Also parking brake light is on. Parking brake is off, fluid O,K. Replaced switch, light still on. Do I need a instrument cluster. Thank you.
AnswerHi Larry,
On the red brake light, that light has two simple circuits:
1. from pin 21 of the 26-pin plug of the cluster which is a black/white wire that runs directly to the switch on the parking brake lever unit. If you remove the 2-wire plug from the parking brake switch then the light should go off. If not, then the black/white wire is shorted to ground somewhere along the path to the cluster or it is conceivable that it is shorted to ground inside of the cluster, but check the black/white wire first to see if you can find a place where the insulation has been punctured by metal.
2. It is also possible that the fluid level warning switch in the master cylinder wire is similarly shorted to ground which turns on that light as well, so look for that at the gray/black wire at its plug at the master cylinder proper to verify that it is not shorted to ground.
On the ABS and Trac Off lights, those (if present) are signaled digitally on a bus wire from the body computer along with many other signals that arrive at the cluster that way. The absence of the ABS and Trac functions in your vehicle is supposed to have been 'learned' by the cluster so ideally they should be not ever lit if the cluster is 'smart' to that fact. I don't know how to re-learn it, however, so you may have to live with it. You could try a cluster self-diagnosis to see if that corrects the problem. Press and hold the trip reset button, then turn the ignition switch to the 'run' position, then release the button. The cluster will do some self-testing after that. See if that changes the situation with those lights.
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Thanks,
Roland
