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1999 Jeep Grand Cherokee P0203 Code: Rear Brake Lights Stay On When Car is Running or Off

Model: 1999 Jeep Grand Cherokee Fault Code: P0203 Posted: 2018-04-29 11:06

My 1999 Jeep Grand Cherokee Limited with a 4.7L V8 engine is suddenly exhibiting a problem where the rear brake lights remain fully illuminated both when the vehicle is in motion and when the ignition is completely off. I do not use daytime running lights or courtesy lights, and all switches are turned off. The brake lights stay on even after turning off the key. Yesterday, the lights briefly went out when I manually wiggled the brake pedal and the wiring harness underneath it, but they returned to full brightness today. The only diagnostic code I'm seeing is P0209 — wait, correction: P0203. I suspect this may not be directly related to the brake light issue. Some users suggest a faulty brake pedal switch might be responsible. However, I'm unsure how to locate or replace it. Can anyone confirm whether the brake light issue is linked to the P0203 code or if it's a separate electrical problem? Any guidance on diagnosing or fixing this would be greatly appreciated.

Related fault codes
P0203
Comments (4)
Anonymous 2018-04-29 12:21

The persistent rear brake lights suggest a switch-related issue, such as a faulty brake pedal switch. The P0203 code indicates a wiring problem with the #3 fuel injector — this is likely unrelated to the brake light behavior. If you're unsure about replacing the brake switch, consult your vehicle's repair manual. A copy may be available at your local public library.

Anonymous 2018-04-29 21:04

Thank you for the clarification! I'm still a bit confused — what does 'one paid for and waiting' mean? Is there a specific document or resource I can access?

Anonymous 2018-04-30 06:40

I believe he means the repair manual, which may be available at your local public library. Many libraries offer access to automotive repair databases.

Anonymous 2018-04-30 12:17

Exactly — visit your local library and go to the desk. Ask for access to EBSCOhost or ARRC (Automotive Repair Resource Center). They will provide you with a login password and user credentials so you can access the repair manual online.