1999 E300 W210 Brake lights on w/ no Cruise Control

[NJ300TD]

I checked out the forums and my car is still running into a problem. Here's the history:

Last fall a bunch of lights lit up. BAS/ASR, Defective Lamp and I had no cruise control. The fix for this was a new brake light switch ($20 at the dealer). Worked great.

A few weeks ago I got a Defective Lamp and it was one of my tail lights. I replaced one and was still getting issues. I cleaned the bulb holder contacts and tail light assembly and put dielectric grease. Still issues so went out and got a new pair (recommended to do this) and replaced the pair.

Now I am getting no warning lamps or Defective Lamp errors so everything looks fine but my brake lights are on all the time and the cruise control doesn't work.

Two things to note: In the process of the cleaning I shorted out the tail light fuse which i replaced with w new 10A fuse. I just got some snow tires and the back tire are 215/60-16 w/ 215/55-16 on the front.

Anyone have any ideas? Do I need another new brake light switch?

[babymog]

Unplug the brake-light switch to see if the lights go off.

[TMAllison]

I believe the brake light switch is adjustable.

[KarTek]

I think sometimes it's posible to get your toe snagged on the pedal and accidentally pull up on it. This can mess up the adjustment. Or, sometimes people do this on purpose too, to try and fix a problem.

[NJ300TD]

OK. I'll pull the brake light switch. When I installed it some people said leave the white plunger alone and others said to pull it out all the way. I left mine alone which meant it was almost the same as the one I pulled. Everything was working fine for a few months until the tail light went out a few weeks ago.

Just started snowing so it will have to wait for tomorrow.

[hobbitss]

Hmmm... Would the mis-matched front and rear sets of tires cause the traction control to disengage the cruise control??

[KarTek]

I think only if the warning triangle is flashing while turning.

[nhdoc]

Originally Posted by hobbitss

Hmmm... Would the mis-matched front and rear sets of tires cause the traction control to disengage the cruise control??

Mismatched tires front to rear absolutely can cause the CC to stop working. In my case it would engage going straight but if you started to turn, even gradually it would disengage. In any case having mismatched tires is a bad idea in a car with traction control and ABS, period. Whether it is causing his trouble with the CC is questionable since he's also having trouble with the brake lights but when my CC would disengage I never got any warning lights - it just would stop holding like I tapped the brake pedal. I could re-set it but as soon as I started another turn, bang...it would drop off again.

[JimSmith]

For my money, go look at the brake light switch. It is the only thing that is directly connected to the brake lights and has a hardwired "shut off" command line to the cruise control system. Jim

[NJ300TD]

I heard about always running w/ the same four tires but i couldn't pass up $60 for two used snow tires 5mm bigger than my stock size. Plus since they were used I figured they were closer to 3mm or less off. With the tires I don't get any warning lights turning, highway or stopping and my cruise control is always off.

This is bugging me so I'll find a dry spot and take a look at lunch. If it is the brake light switch should I pull the white plunger all the way out before putting it back in? It seems like stepping on the brake after that would reset the plunger at the right spot.

[nhdoc]

Originally Posted by NJ300TD

I heard about always running w/ the same four tires but i couldn't pass up $60 for two used snow tires 5mm bigger than my stock size. Plus since they were used I figured they were closer to 3mm or less off. With the tires I don't get any warning lights turning, highway or stopping and my cruise control is always off.

This is bugging me so I'll find a dry spot and take a look at lunch. If it is the brake light switch should I pull the white plunger all the way out before putting it back in? It seems like stepping on the brake after that would reset the plunger at the right spot.

There is about 3.2% difference in the circumference between your front and rear tires. Like I said above, I don't know if it is the cause of the CC problem, and I suspect not, but it is just not a good practice to use any different sized tires on these cars.

[hobbitss]

I've been wondering about this part of the original post...

Originally Posted by NJ300TD

A few weeks ago I got a Defective Lamp and it was one of my tail lights. I replaced one and was still getting issues. I cleaned the bulb holder contacts and tail light assembly and put dielectric grease. Still issues so went out and got a new pair (recommended to do this) and replaced the pair.

Now I am getting no warning lamps or Defective Lamp errors so everything looks fine but my brake lights are on all the time and the cruise control doesn't work.

Two things to note: In the process of the cleaning I shorted out the tail light fuse which i replaced with w new 10A fuse. I just got some snow tires and the back tire are 215/60-16 w/ 215/55-16 on the front.

Anyone have any ideas? Do I need another new brake light switch?

Is it possible that he has a short in a tail light housing that is causing the brake lights to stay on and with the brake light circuit hot keep the Cruise control from working???

Still Thinking.....

[NJ300TD]

Finally got some time to get to the brake light switch. Pulled it out and it looked OK but the white plunger was all the way in. I pulled the plunger all the way out, put it back in place and the brake lights are off!

OK, so the brake lights work and there are no error codes but the cruise control still doesn't work. I even tried turning the steering wheel lock to lock.

I don't use the cruise control so it's not a big deal but i'd still like to know.

[TMAllison]

My guess is the tire diameter is sufficiently diff to prevent it from working but not sufficient to set off asr/traction codes.