Is the break light mod safe?
 

Hi all,

I have a 2003 MCS with 83Kmiles on the clock. For the last 50Kmiles, I've had the brake light mod using a "jumper" cable connecting brake lights to the fog lights.

Yesterday, I realized that one of the fog lights was out -the brake light on that side works fine. While trying to see what kind of bulb it is, I've read few posts (some dating back to 2005) discussing whether this mod actually overloads the BC1 with two extra 21W bulbs and cause its failure resulting in an expensive repair.

I know there are quite a few MINIs (02-04) with this mod out there. Now after seeing incidents of BC1 failures, I am trying to decide whether to just replace the burnt out fog light and enjoy the extra visibility when breaking or to be on the safe side and pull the cables disabling the mod.

Any advise or feedback would be appreciated.

Thanks!

I haven't done the "jumper cable" mod, but if I were considering adding an additional 42 Watts of load, I'd feel safer adding a relay. Have the relay supply power to the fog lamp, and have it triggered by the brake light wiring. The current draw on the BC1 module from the relay would only be around 1-2 Watts.

I would only do this mod with a diode. I have done over 50 of these mods with no issues ever and always used a diode

Thanks for the suggestion.

I just took the cables -and the mod- out. Yes, the bulb is gone; everything else works fine...

Is there a "how to" on doing this mode with a diode? It's been a while since I did this :grin:

Is your car wired for the rear fog already (toggle switch in the dash and all that), or did you just add a rear fog assembly in order to get the extra bulbs to hook into the brake light circuit? Because if you just had a simple jumper wire connecting the brake light wire to the fog light wire, how did you keep your brake lights from coming on when you turned on your rear fogs if you didn't have a diode in the circuit already?

A diode will only allow current to flow one way in the jumper wire, so hitting the brakes will turn on the fog lamps, but turning on the fog lamps won't cause the brake lights to come on. Basically, the diode will have one end with a stripe on it. Run a jumper wire from the brake wire to the non-striped end of the diode, then run another wire from the striped end of the diode to the fog lamp wire. Since the two fog lamps are 21 W each, I'd use a 3-amp diode to make sure you don't overload it.

Note that using a diode doesn't reduce the extra load on the BC1 module - it's still going to have to provide the extra 42 W for the fog lamps. If you use a relay instead of a diode, it will solve both of your problems, since it will prevent the BC1 from having to power the fog lamps, and it will electrically isolate the fog lamp wiring from the brake light wiring, so you wouldn't need a diode.

I have had jumpers with no diode in Artoo beginning a couple of weeks after he arrived in October 2002 (built the first week of the 2003 builds). No problems what-so-ever. I like the added bit of protection and when my bulbs burn out, I will simply replace them. For the longest while I kept a bag of jumpers and did the mod for anyone that asked and there are a lot of them still around and not a single one has ever complained.

I say this mod's downside is busted!

Rich

PS-I use 14 gauge wire bent into a U and pushed into the connector. With thinner wire and bad connections your milage may vary.

So if you don't have a diode, what keeps your brake lights from coming on when you turn on the rear fogs? Or do you just not activate the fogs manually from the toggle switch once you've installed the jumper?

I don't have the fog light option, but have been brake light mod (and no diode) since August 2002 without problems..

Thanks for the explanation and the suggestions.

As many on this board, I dont have rear fog assembly. We are just using the intact -but otherwise useless- rear fog light circuitry and the bulbs.

I may just go ahead and re-install it, since my commute involves lot of breaking on the freeway with sudden change in traffic flow.

How about going with LED bulbs. I know that they are not as bright, but they add so little (1/10) to BC1.

Cheers!

This mod as described is for pre-facelift 1st gen cars. The post facelift cars (including cabrios) have the foglight in the bumper. They can still be modded for similar results using a diode or kit from gominigo.

After being rear-ended, I installed the Add a Brake Light Kit from Minspeed a year ago on my early non rear fog '05. The fog wiring harness was not in the early '05s so I had to get the kit that came with the fog light, plug, and short harness to splice into the left rear brake light (non diode). The diode version kit connects the OEM fog harness to the brake wiring, so it will work as both a brake light and a fog light. Mine does not work as a fog light. Obviously, since I'm lighting up the single fog light instead of 2, I'm not using as much power, but I've never had a problem with it. Between it and the pulse 3rd brake light kit, it seems to keep people off of my back bumper. I just don't think they would sell the conversion kits if it would ruin something.

I had installed the jumpers a few years ago, and last year, my body control module (BC-1) needed to be replaced. That is a very expensive part!

Luckily, my dealership replaced it for free, even after my warranty was expired, but I have a suspicion that it was these jumpers that were the culprit.

The symptoms were that all of the sudden, my rear brake lights were constantly on, at full intensity, even with the car off, and THE KEY OUT OF THE IGNITION!!!

Yes, that's right.

So, I would have to disconnect the battery everywhere I went, or else it'd be totally dead within a couple hours. That was a major hassle. It had to be flatbedded to the MINI dealership, and like I said, they fixed it; unable to find the root cause. They suspected something with the lighting system, though, and warned me that should the BC-1 fail again, the would NOT replace it gratis again...

So, in summary, I really recommend against the jumpers.

Jonnieoh,

The situation you discribe is a know BC1 failure and there is a notice on at the MINI Dealer. These failures have been isolated and can not be traced to the mod. Our 'Give Me A Brake' kit is for MINIs with or without rear foglights installed and each wire has diodes installed. Our 'Add A Brake' Kit is for MINIs without rear foglights installed. This gives the owner an additional brake light to make the back more visible.