Thanks for the pics.....the top tail light which is now the LED looks to me just about as bright as the bottom filament lights. I hadn't thought about the more LED bulbs being a larger diameter and not fitting the lens housing without having to enlarge it.

 

Sorry for digging up such an old post.

So I had my rear brake light mod on my 2004 MCS for a couple of years.

Recently I am experiencing the same problem as described
left brake lights did not work only turn signal worked.


The dealer said it is the BC1 problem, after charging me a $3xx fee for diagnosed and now they are telling me it requires additional $1000 fee for BC1 replacement and programming.
They said that upon resetting of BC1, my rear brake light would work for a couple of seconds and then stopped working again.

I can't really afford the extra $1000 at the moment, so I told them I am going to get my car back.


To my surprised, after I got my car back and when I checked, my rear brake light IS working!!!


However, two things fail to work on my car now.

1) the remote control

2) My automatic climate control a/c (dealer said bcoz the BC1 is fried, in order to fix the a/c, I'll have to pay the $1000 for a BC1 replacement)



Thanks alot!

 

Definitely remove the brake light mod if you've not done so already!
Maybe the BC1 is flaky and will work for a while and fail again some time. Or maybe you got lucky.

Either way, demand they sort the unrelated (remote, a/c) at no cost to you, assuming it was all fine before the dealership touched the car. If they caused it, they fix it, no matter whether or not they fix the issue you asked them to look at.
They charged you $$$ to investigate - that money paid includes the expectation that they don't break anything else while investigating the original issue.

It's likely they somehow factory reset the BC1 and didn't properly reconfigure it to your remote and car options; you might find some other options (fog lights for example) are not working too. It's an easy job for them to properly reconfigure your BC1 back to how it was from the factory, and it's certainly not your cost for them to correct what they messed up.

 

Thanks for the quick reply!

Yes I have already removed the brake light mod.

When I asked them about the a/c problem and told them it was all fine before the dealership touched the car, they claim that it is due to my faulty BC1. They claim the BC1 controls the auto a/c, so in order to fix it, i still have to pay the $1000 to replace the BC1.

If i recall correctly, I read somewhere before, if one resets the BC1, the dealer ship has to correctly program it for stuff like remote,auto a/c/ fog light,...etc to work....

However, my dealership did not even try and just told me,
i have to replace the BC1 to fix the problem.

They said they could try, but it will cost me another hour of diagnoses fee......

 

I have the 1156-R24 (narrow beam) lights in the fog light position and they fit without modification (3/2003 MC).
They're not quite as bright as the stock bulbs, but good enough for me.

 

Mine have been jumped since December 2002 with no trouble what so ever. I have a pulsing brake light too.

Rich