Strange Problem With Brake Light

ndking1126 · October 22, 2012

I'm used to working on my 1985 Jeep, but this is rare that I'm working on my Lexus.. I have an 01 ES300 with approximately 145K miles. It is in excellent condition and I almost never have to do repairs (other than maintenance, of course).

On my dash, the Rear Light Failure Warning indicator stays on. If I turn on my headlights, all the lights in the back will light up as they are supposed to. If you push the brake pedal with the headlights on, the driver brake light gets brighter and the center brake light comes on as they should, but the passenger light doesn't change.

If I push my brakes without the headlights on, the passenger brake light does not come on. The driver and center brake lights do come on, however

I know the bulb isn't burnt out. Somehow the signal isn't getting to the passenger light that the brakes are being depressed. I dont know what that part or relay would be called. Where do I start? Thanks for your help!

gbhrps · October 22, 2012

Sounds like a bad ground to that light, or a bad connection.

1. Pull the bulb, clean its contacts and the contacts in the socket. Reinstall it and check the problem.

2. Change the bulb. It may look good, but may be failing.

3. Search the wiring back on the harness to the first ground you find, clean that up, or add another wire to the ground on the socket and fasten it securely to a good ground on the body somewhere behind a panel. Good Luck!

landar · October 23, 2012

What you have described sounds exactly like a burned out bulb on the passenger side (right side). When you turn on the headlights, the tail lights come on all the way around as they should. The tail lights are a separate filament from the brake light filament. In other words, the brake lights do not depend upon the headlights being on or off.

The warning indicator is showing that not enough current is being drawn by the rear lights. This could be due to a burned out filament in the brake bulb or a bad connection as gbhrps suggested. Do not depend upon a visual check of the bulb filament. Try a new bulb(or use an ohmmeter) and look carefully at the socket connections for corrosion and wires leading up to the socket. This is most likely something fairly simple especially if it just occurred quickly and is not intermittent.

ndking1126 · October 23, 2012

Thanks for the replies. I did not know the brake and headlights were separated like that. Looks like I found a project for this weekend! Hadn't really thought of checking its ground or connections either.. I was making it more complicated than it probably is. I'll definitely report back if I find overly interesting!