JAB

Your problem description is unclear. Is your bulb sensor on but you can't figure out why? If so, be sure your center high-mounted stop light (CHMSL) is not burned out.

insuralife

Sorry..
No sensor light on the dash is on. The brake lights worked a month ago when I replaced a blub. Now, nothing... Had it not been for a benevolent cop, I still wouldn't know they didn't work!

salimshah

So are you getting +12v on G-R and G-Y wires out of the sensor module (when brake is applied)?

If not then Check the G-W wire coming in (when brake applied)?

Salim

ps: thank you for keeping up with me as I manage these threads. (moving it out of the mega thread and merging it with another and then merging again). There are two different problems being discussed here, but the circuit diagram is here.

salimshah

Barbwire54:

Try removing the stop fuse. If the brake lights remain on, then +12v is leaking in from some place other than the brake circuit. You can progressively remove connectors from the brake module and that would narrow down the leak to +12v progressively closer to the brake light bulbs.

Salim

insuralife

My problem (among many!!) is that I can't find that sensor! I have current on th G-W..
I see the harness in the rear, and I have a pigtail with an unused white connector, and the a black connector with a jumper cap on it. This at the tire well and the gas door inside the car..
Thanks! Many thanks...

insuralife

YOU RE KA !!! I FOUND THE PART!
1st thanks to those that sent messgages trying to help..
OK, where was this little bugger? Well, when you take off the left side trim panel below the plastic one that goes up to the roof, you will see the rubber drain hose for the sun roof. Behind it, attached to the metal structure, you will see the BACK of the plastic pin/clip that holds the box in place. The box actually faces to other shell of the car and you can't see the box itself! Look for the brown tab of the pin/clip.
I jumped the green-white with the green-red and green-yellow, and presto it works great! Now to get a deal on the actual part, or the jumper stays in place!!
Again, thank you......

insuralife

OK, I learned an additional fact or two about that dastardly sensor. IF you jump the wires Green with the white, red and yellow stripes AND plug the connector back into the sensor, the dash lite will come on for a failed bulb. IF you don't plug it back into the sensor, the taillights won't work!!
SO you end up having to clip the wires, however, leave enough tail from the connector that when you do replace the sensor, you can do a neat soldering job!
In reassembling the parts and the trim panels, I had taken the hard plastic panel off as well. When I reassembled it all, I realized that the sensor is attached to the body frame-work about 4 to 5 inches above what you can see. SO... WHen you have this problem, remove the lower trim panel only, slide your hand up the harness and right behind the drain tube you'll feel that box.

If you are like me, after you're all done and everything works, you'll want to take that part into a darkened work shop where you keep your torch, dull chisels and dull punches.. Slowly burn that plastic off that sensor and as you drive that punch through it's little heart, imagine it's the damn engineer that designed it and it's location!! Yes!! HE/She WILL feel it!!

Barbwire54

@Baetke - My issue is with the actual rear lights , not the stop lights which work fine when the brake is pressed and go off when the brake is released. I plan to follow up on salimshah's advice about the possible corrosion in the towing light connector but was hoping you might have a wiring diagram for the rear lights. Again the brake lights are fine, the rear lights that come on with the headlights come on randomly whether the vehicle is running or not. When it happens I can hear a switching sound inside the compartment in the driver's location.

Thanks to you and Salimshah for your assistance. I will continue to try to discover the cause of this mystery symptom.

insuralife

Barbwire... Is the towing connector that white colored plug that is by the upperend of the spare tire? In diagnosing my problem, I came across 2 plugs, one that was black and had a cap on it, and the other, white, just open ended. Seems there was power from the lights on that plug.

insuralife

BArbwire. I sure hope your problem is a minor one. I just got a callback from Lexus of Clearwater (FL) that the brakelight bulb failure sensor in now up to $461.00 retail!!

Baetke

See if this helps...

insuralife

WOW........ That is one helpful schematic! I hope there is a place were all these things are stored here on this site...

Barbwire54

OMG 461.00??? I decided to buy the control arm located on the left of the steering column as you sit in the driver's seat. It is there that I hear the clicking that is in sync with the taillight turning on and off which they sometimes do several times in a minute before they either shut off or stay on until I removed the battery cable. I haven't installed it yet but for 50.00 I thought it might be worth a shot. It has switching mechanism(s) built in so I will let you guys know if they were the failure point or not.

Barbwire54

Oh and thanks for the schematic. I saved it and will try to figure it out later this week.

Barbwire54

The towing connector I referenced is the one located on the tow bar where the trailer lights are connected when you plan to use a trailer. There was some possibility that moisture was entering there and causing problems.