strange wiring modification done in back of car. i bought this car, and not sure if the brake lights ever worked. but someone waved me down the other day, and said my brake lights weren't working properly.
i am thinking the wiring in the hatch must have something to do with the problem. see pic below.

 

yea....that ain't good......someone had their fingers into this and should not have......

What year is your car, what tail lights do you have?

Those two little connectors at the right are for the dealer installed 6 disc CD changer......so ignore those for now.....

you are gonna need to take out most of the trunk panels to gain access to the wiring harness's......and yes, I meant more than one harness is back there

Bryan

 

its a 2003 cooper s. see the taillights attached.
by the way, when the headlights are on, the third brake light stays on as well as the bottom portion of these taillights.
when i hit the brakes, nothing else lights up.
so, i need to remove interior panels to get to the trunk wiring harnesses.
what would be the next step?
thanks for the help.

 

yes, I would remove the trunk inside panels to gain access to all the wiring that has been butchered......then I would remove that blue wire harness that has been added and try to put all the butchered wiring back to stock if you can.....be very careful on the colors of the wires, some are so close to matching that they really don't match...

Or, find someone parting out an "03 R53 and take the entire rear wiring harness's out to put in your car.......which may run to the front of the car as well.....

even if you get all the wires put back to where they go.....you still may have electrical issues back there....maybe they were trying to by-pass something that doesn't work anymore......maybe a module is bad.....

The first thing to do is to put the wiring back to stock and then see what happens......that's about all you can do for now.....

Bryan

 

Where does the blue cable go?
Does the car have/had a tow hitch?

On the early cars, the bottom light is the stop/tail light.
The middle amber light is the directional. That's the minimum legal requirement.

The top light could be a brake light or rear fog light or may not work at all - that depends on programming. I wouldn't worry about it for now.

Yes, get the blue cable out of there - Bryan had the right idea.

PS - a common problem is burnt/overheated connectors & bad grounds - check those while you're in there.

 

Looks like the car had aftermarket amp, sub woofer, etc. in the car that was pulled out. A competent stereo installer who knows his/her stuff could probably sort that out with a good wiring diagram.

Where are you located? Someone might have a recommendation for you.

 

Looks like Stinger 5 conductor speedwire, used for an aftermarket stereo setup. Haven't used the stuff in a long time. That shouldn't be used for the brake lights but you should check it out to see where it leads too. Are there aftermarket speakers in your MINI?

 

the blue wire leads up into the dash.
the radio was changed at one point, and it has bluetooth.
there are no markings on the bumper where it would have ever had a trailer.
i like your thoughts about leaving it alone. i do have a third brake light and the bottom tailights are lit, but nothing happens when i mash the brakes. DMV seems to suggest a car needs stop lights?

 

I am in the Jacksonville, Florida area. so many stereo places have shut down, i would love a recommendation. thanks for the suggestion.

 

thats very insightful about the blue wire.
the car has a newer stereo with bluetooth, but the speakers seem original.
so far, it leads into the dash, but let do a little digging and let you know.

 

Are your speaker grills marked Harmon Kardan? I think the previous owner removed the HK amp (which likely had failed) and connected the aftermarket headunit to the existing HK speaker wiring. If the blue cable goes to the headunit and the stereo works, it is probably wired correctly. Your brake light issue is probably unrelated.

 

Yeah, that's all stereo stuff - shouldn't impact the brakes at all. I'd start with checking the bulbs. The whole assembly pops out after removing a screw or two.

 

yes RKW. the speakers are marked Harmon Kardan.
so thats a relief the problem is unrelated.
ok, the blue wire isnt the issue with the brakes.

 

thanks Eric, let me check bulbs and circle back in a minute.

 

the third brake light coming on with headlights is not right....it should only come on when brake pedal is pushed.....along with the lower bulbs in your tail lights.

The lower bulbs should have two filaments, one for parking lights, and the other for brake lights. The center bulbs in the rear lights should only have one fillament for turn signals. The upper bulbs in the lights should only have one filament also, those are for the factory rear fog lights, which most didn't have coded for the car.....I would just pull those bulbs out and check the others for the correct bulbs.......then we go from there

What bothers me most is the third brake light coming on with the parking lights....

Also, check your fuses

Bryan

 

okay, I replaced the lower bulbs, and yes, they have two filaments.
This might help the troubleshoot, but BOTH filaments in both lower bulbs are burning.
as if, the brakes were mashed. which would coincide with why the third brake light is on.
(the car thinks the brakes are mashed, so it all lights up)

so, i bought a new brake light switch from NAPA, and it didnt fix the problem. and, i have disconnected the battery a couple times to see if the brain will reset.

i have pulled back the passenger side trim and checked the condition of the BCM, because some suggest it gets weathered from leaky sunroofs, and it fouls out the diode. but, it appears, high and dry.

i'm thinking to purchase a new brake light switch from the MINI dealer tomorrow instead of the one i have from NAPA ?

please advise,

 

If both filaments are lighting up when lights are on, then you have lost your ground connection to the body somewhere

I think it is the solid brown wire. Grab a test lead and clip on end to good ground on the car, touch the other end to the side body of the lower bulb when you have the lights on and see if the one filament goes out.

I would not worry about another brake switch at this point, fix the known problem first

Bryan

 

So it looks like the diode near the bcm is the culprit. It disintegrated in my hands. Going to get an original from the dealer . Does this need to be soldered or slid in ?
the dealer is charging 50 dollars for a diode and will take two days to arrive . Is after market part ok ?

 

A generic replacement, with appropriately-similar specs, will be an adequate replacement.

Dealer-sourced electronic bits are always comically-priced (and not in a good way...).

 

yes. the diode from the dealer was comically priced indeed. $45 plus tax. but, i plugged and now i can play.
thanks everyone for your input. the diode was the problem for sure, and now the brake lights are working perfectly.
time to buy some modern taillight retrofits !