Puttster

My daughter's car, so of course I have no idea how long the brake lights have been out, although it passed inspection six months ago. Anyway, fuse was okay. With the help of this forum, I pulled off the rear panel and got to the Brake lamp failure sensor module. Testing, I got 12v on the green-white pin coming from the brake light switch at the pedal, so its not that switch.

When I jumped that pin with the green-yellow, which supposedly goes to the brake lights, only the high 3rd light went on.

Are all the brake lights coming from that same green-yellow circuit? The last few inches of the wires going to the lower outside lamps are G, G-W and W-B. Wires to the lower liftback lights are G-R, G-O and W-B. I don't see any obvious issue with the soldering on the module, but I don't know much about it or how to check it. Thoughts?.

Puttster

I have been able to narrow the problem down to the module. Gone to a half dozen junk yards and concluded all the modules in all the RX300s in all the world have been removed. The used ebay ones run $100. I would get one but I am afraid that people buy them then "return" their old broken ones for refunds and all that are left are those broken ones.

Any final suggestions on repairing my old one before I pull out my never-before-used soldering iron and attempt a cure?

maxSteel

If I understand the diagram

• R-L is power to the module (pin 8)
• G-W is power in from the brake light switch (pin 7)
• R-Y is the signal to the rear light warning light (pin 4)
• W-B is ground (pin 11)
• G-R is power to the two lower stop lights (pin 2)
• G-Y is the high mounted stop light (pin 1)

So you can verify the lower lights by powering G-R.
Does R-L have power when key is in ACC or ON position?

JAB

Please show us exactly where this module is located.

Puttster

Not sure about a R-L wire, the first slot in the module (and connector) is open, followed by the slot with G-W, which is power from the brake switch. If resoldering the three connections does not work.I'll have to buy one somewhere.. Meanwhile to make it drivable I'm thinking about putting a jumper wire on the connector, jumping G-W and G-R.

maxSteel

I may be seeing it wrong but to me your photo shows W-B (ground) on the other end of the connector, not next to G-R as in your drawing.
I also see more wires in your photo than the wiring diagram I looked at showed. My diagram had 6, your photo has 8 I think.

Leaving the extra two aside, how do the pin numbers (should be on connector back) match up with what I provided?
Based on the wiring doc, the module needs its own power supply. That supply is also fuse protected.
You should be seeing a hot line when the key is in ON or ACC.

maxSteel

Found a chart for that connector. For all pins connect tester to ground

1: constant, continuity to ground with some resistance (because circuit is ground through bulb.)
2: constant, continuity to ground with some resistance
9: constant, continuity to ground with some resistance
11: constant, continuity to ground
3: light control switch OFF, no voltage
3: Light control switch TAIL or HEAD, Battery positive voltage
4: Ignition switch LOCK or ACC, No voltage
4: Ignition switch ON, Battery positive voltage
7: Stop light switch OFF, no voltage
7: Stop light switch ON, Battery positive voltage
8: Ignition switch LOCK or ACC, No voltage
8: Ignition switch ON, Battery positive voltage

Puttster

I think you are right, I have mis-labeled the W-B ground. However, I have some good news. In the connector I put a jumper between G-W and G-Y+G-R. Tested the brakes and everything worked fine.

Then, on a why-not Hail Mary, I got a soldering iron from Radio Shack and re-soldered about ten points on the module. Put the module into the connector and Va-voom! Brake lights work. My first ever soldering and oh lord what a mess (see pic) but amazingly... well, the rest is history.

maxSteel

I think I would have first verified the pins were correct as described by the diagnostic.
If they were all correct I would next have checked this:
https://www.clublexus.com/forums/rx-...or-module.html

No idea if shorting those together could have side effects.
You may also have been able to jumper the connector and bypassed the sensor module entirely, with the only likely side effect being extra draw on the brake switch circuit.

Puttster

In the connector I put a jumper between G-W and G-Y+G-R. Tested the brakes and everything worked fine

Dolo456

Thanks to this thread I fixed the part in less then 1 min. Would have cost me 500 at the dealer!!! Thanks so much!!!

maxSteel

I visit a number of car and motorcycle forums. This one has been the most useful by far.
Great group of contributors and moderators.