CELSI0R

Nice work! I'm glad that you and Yamae were able to find the fuse.

Once everything is back to normal, could you share the info you found on the warning light module?

CELSI0R

Just bumping this thread.

Any chance of having the info on the warning light module you found? Thanks.

peterls

DISCLAIMER: THIS IS FOR GEN 1 LS400. MINE IS 1990, SO I IMAGINE EVERYTHING IS THE SAME FOR 1991 AND 1992, BUT I DON'T KNOW ABOUT 1993 AND 1994 - SOMEONE PLEASE CHECK IF THE WARNING LIGHT MODULE IS THE SAME FOR 1990-1994 OR NOT.

So, it took a while but it's finally done. The thing that gave me trouble in trying to figure out which wires to connect exactly was the fact that brand new Sylvania light bulb was broken. To play it safe, I replaced all my rear bulbs with brand new ones. But one of them would not come on no matter what... and thinking - "its brand new one, it cannot be broken" I kept trying and testing and trying and testing... until I finally tested the bulb, and sure enough - it was broken right out of the box.
Anyhow, here is the lowdown on what to connect to bypass the rear stop lights / brake lights module:

I will post here two descriptions: one is based on wire colors, the other on positions within the module's plug. Same result, same thing, just different description (in case you are color blind, or cannot see the difference between say purple and blue or pink and orange very well as it is hard to see things in that jungle of wires there).

BTW, initally, to test things out, I used the "OBD-1 tool" (insulated paper clips like these: https://pixabay.com/en/paperclip-clip-office-178126/) cut in half so I end up with two "U" shaped wires, with some of the insulation removed at the ends and just plugged them in as I was testing the connectors. This worked, but eventually, they get pushed out and get only partial contact which melts the connector. Not a good thing. So OK for testing if you really must test, but not for more than a few seconds at a time, if that.

First of all, the plug for the warning light module is located in the trunk, on the driver's (left) side, right next to the Pioneer stereo amplifier. So you will have to bend that carpeting there to get to it. Its similar to accessing the antenna motor and such... no big deal. The warning light module is black and it says "warning light module" on it - it's just raised letters, black on black so hard to see, but the name is there. Don't know the part number, threw it out in frustration.

Now, if you pull out the plug from the Warning Light module, it will have two rows of contacts: one row (let's call that one "right") will have SEVEN contacts, ALL have wires coming to them and all are doing something. The "left" row (the other one) will have also seven spaces for contacts, but two of them are blank - nothing there, just white plastic. If you orient the plug in such a way that RIGHT side = all SEVEN connections, and LEFT side = two blank connectors, than those two blanks will be #3 and #4 from the top, like this:

o o
o o
x o
x o
o o
o o
o o

you get the idea.

Now, the third connector from the bottom, on the left side, is blank - no wire leading to it.

And now the schematic:

"B" = "Brake light connector"
"L" = "rear light connector"
"N" = "don't do anything with it - ignore it even if it has a wire in it".

If you do connect the "N" wire, you will most likely blow out bunch of fuses and burn who-knows-what (in my case the alarm system went bonkers and few other things).


L L
N N
N B
N N
N N
B L
B B

As you can see, there are four wires for brake lights and three for the rear lights. I was initially planning on opening the warning light module and soldering those connections together, so that I could plug it back in for a nice clean look, but ultimately ran out of time and just snipped those wires and soldered them together. It is a ***** to try and solder those wires like that - they are short, in the corner of the trunk, I was fighting the carpet, and cold and windy weather here in N. California yesterday and it took forever to warm up those wires and the solder (use thinnest solder you can find)... so bring tons of good mood and nerves of steel (and a more powerful soldering iron than I had) if its cold while you are doing this.

Here are color codes for wires that need to be soldered together:

For the rear lights:

Thin green wire with red dots (top left corner of the plug) + thick light green wire right next to it + thin green wire with orange stripe and two pink dots every 1" on the opposite end of the plug.

Those need to be connected together for your rear lights to work.

Now for the brake lights:

Thick yellow solid wire (in the bottom corner of the connector) + thin green wire with yellow stripe (right next to the yellow one) + red thin wire with white stripe (right above the yellow wire) + Thick green wire with white stripe (which is on the other end of the plug).

Connect some other wires and you will be going through major pains like I did - fuses popping, alarm going off, and all kinds of gremlins... so "kids, don't experiment, just follow the above". Obviously, do not follow the above if your plug and wire colors do not match this description!

Good luck and let me know how it went!

ps. should we post this where it would be easier to find?

CELSI0R

Thank you for all of this great documentation!

I look forward to referencing this when troubleshooting soon.

python

iTrader: (4)

bump for reference...no brake lights! ordered a switch..hoping thats the problem