Brake light problem

Tiny
BILLG1960
  • MEMBER
  • 2001 JEEP GRAND CHEROKEE
  • 4.0L
  • 6 CYL
  • 4WD
  • 240,000 MILES
The passenger side brake light does not work. Replace the bulb tried a different light assembly and still does not work. Looking for the color of the wires that go from the brake switch to the light assembly or any other information that would be helpful. Thank you.
Monday, April 17th, 2017 AT 2:20 PM

3 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,737 POSTS
The wire between the brake light switch, and the three rear brake lights is white/tan. The turn signal switch is not involved because the stop lamps and the signal lamps are different bulbs.
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Monday, April 17th, 2017 AT 4:19 PM
Tiny
BILLG1960
  • MEMBER
  • 2 POSTS
Thank you. The tail lights and turn signals all work fine, it is just the passenger side break light. I will try to trace the wires, you wouldn't happen to know how the cable is routed to the back? Or any trouble spots?
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Tuesday, April 18th, 2017 AT 9:29 AM
Tiny
CARADIODOC
  • MECHANIC
  • 33,737 POSTS
I'm actually helping someone else for this same problem on a Wrangler right now. For yours, there's two splices involved in this circuit. The first splice has three wires leaving, ... One to each brake light. The wire to the right brake light has another splice, and that second wire goes to the Anti-lock Brake Computer, (CAB), if you have anti-lock brakes. That splice is simply listed as, "near stop light switch". If you have a Chrysler service manual, that will have a pile of drawings in Section "8W" showing the location of every splice and every connector.

Normally I would suggest connecting a scanner that can access the Anti-lock Brake Computer, then observe if it recognizes when the brake light switch turns on. The problem is we still wouldn't be able to use that as a clue to narrow down the location of the break. A corroded spice could result in only the brake light not working, only the ABS Computer not getting the signal, or both. The only thing we could learn is the wire has to be good up to the splice if either item works.

If you have ABS, can find the computer, and can get to the connectors to back-probe them, terminal "18" is the brake light wire, and is still a white / tan wire. An easier clue is to observe if the ABS does its thing when you force a skid on a dirt road. The computer will not pulse the control valves unless it sees the brakes are being applied, and it knows that by the brake light circuit we're discussing.
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Tuesday, April 18th, 2017 AT 7:22 PM

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