had the same problem .... solved it with a new brake light switch at the pedal ....

Could you elaborate on how to R&R a 129 Brake Light Switch p/n 0015450109 ?

 

Could you elaborate on how to R&R a brake light switch?

It's very easy. You'll have to crawl into the driver's footwell headfirst with a flashlight. Look at the brake pedal. At the top of it you'll see the brake light switch. Unplug it, and pull it out. I think you'll have to turn/twist it 45-90 degrees to let it release? I can't remember if it's on the firewall side of the brake pedal or towards the driver's seat.

 

It's very easy. You'll have to crawl into the driver's footwell headfirst with a flashlight. Look at the brake pedal. At the top of it you'll see the brake light switch. Unplug it, and pull it out. I think you'll have to turn/twist it 45-90 degrees to let it release? I can't remember if it's on the firewall side of the brake pedal or towards the driver's seat.

You are correct that you'll have to turn the steering wheel lock to lock afterwards to reset the system.

 

Hi I replaced mine just before Christmas. It is above the brake pedal under the dash board. You need to remove the panel under the steering wheel to get access.

To remove the switch push in the clip sticking out as shown in your picture and then twist the part 90 degrees it should then pull out. I removed the electrical connectors first.

The way I knew it was the switch, was my abs, bas and asr lights all came on at once. When I started the engine with the brake pedal depressed the lights would not be light, as soon as I let the pedal out the lights would come on. If I started the engine without the brake on, the lights would come on straight away.

Hope this helps

Ian

 

...The way I knew it was the switch, was my abs, bas and asr lights all came on at once. When I started the engine with the brake pedal depressed the lights would not be light, as soon as I let the pedal out the lights would come on. If I started the engine without the brake on, the lights would come on straight away.

Hope this helps

Ian

Good way to test if its the brake switch. Will definitely store this idea in my brain for future use. :thumbsup:

 

Thanks for the quick response.

 

Thanks for the quick response.

Regards, Lynn

 

Can that switch be open up and cleaned ?

 

I think one of the posts that I read suggested that the contacts could be cleaned but at $21.10 NEW it may be better just to replace it with a MB part rather than a $9.00 URO part.

 

haha wow what are the odds.

my car today just as i touched the pedal the ASR,ABS light BOTH come on at the same time when i hit the brake to disengage the Cruise Control.

now when i start my car all is good. but when i touch the brake pedal the ASR,ABS lights come on both. those damn things are VERY bright and noticeable with these strips. especially when they are right next to each-other.

i plan to do some more checking tomorrow though to make sure i am not missing any symptoms. though for $20 i think i may just replace it anyways as it isn't a big expense at all.

 

though for $20 i think i may just replace it anyways as it isn't a big expense at all.

Did you replace the $20.00 Brake Light Switch?

 

yes that's how to change it but I'd pull the plunger of the new switch out a bit so it will seat against the pedal .... I didn't do that at first and my brake lights didn't function right ... can't remember if they'd even go on at all?..... did it again and pulled the plunger out a bit and all was fine

Regards,
Fast960

 

I changed mine almost right after I got my car. And as long as you are in contortions accessing this why not replace a similar switch for the parking brake?

At least that's what I did.

That brake light switch can be the source of all kinds of weird electrical glitches.

 

why not replace a similar switch for the parking brake?

Good idea. How about a p/n please???

 

that switch is a bit more hidden then i thought it would be. it was also a pain to get to the switch with such small space to work in.

good news though.

Cruise Control not working. ASR, ABS, no Brake Lights all because one of the two plugs for the switch had come undone. someone at some point doing work down there must have not clipped the connector in properly.

that small switch really can cause weird, unexpected problems.

 

It's a pretty common problem. I have done it each in my old 300E and now the SL500. My family's 2000 E30 had the BAS-EPS light come on and my independent shop diagnosed as - you guessed it - the brake light switch. He replaced it and it took him maybe 20 minutes.

But he has had more practice ;-)

He said something interesting - the newer cars have 6 connectors in that switch - more things to throw off, I guess.

 

Hello everyone, I'm new to this forum so please forgive me if I do something wrong. I have a 1998 SL500 that I've just replaced the brake light switch in because of my asr & bas light coming on, cruize control stop working & rpm's fluctuating up & down along with limp mode. It didn't fix it, so I put it in drive & while moving I put it in neutral, turn the switch off, restart while coasting & all goes away.

 

Sounds like it could be a neutral safety switch problem. I'm sure there will be some info on the search engine somewhere to help.

 

sounds like an electrical problem .... low battery perhaps .... or you are charging a cellphone or two .... could also be the base module and there is a fuse in it .... I've also heard of an acceleration sensor causing this but I'm not familiar with that component ...... Usually these are relatively easy fixes, it's just narrowing it down and finding the culprit .... I'd start by checking the battery then the base module ....
Regards,
Fast960

 

I had this occur a couple times when I had extra things plugged in the cigarette lighter ...ie garmin + battery charger .... and once when I was changing the bulb in the cigarette lighter .... the episodes were 3 years apart and no re-occurrences .... I believe voltage spikes caused the problem .... and both times I was either parked or in stopped traffic .... I'm now careful in plugging extra devices in ... especially when idling

 

I do have my phone charger in but not connected to the phone everytime when this happens. The bas asr light comes on sometimes while driving but it doesn't effect anything unless it's on when it starts. I have a rear side marker light that I have to tap sometimes to come on but it doesn't seem to effect it either. I'm going to get my battery tested again tomorrow. Today it ran like a champ, after it stops snowing I'll get back to work on it & post what I'm doing.

 

1993 SL500 ASR LHM

I'm still having problems with the ASR light coming on and going into LHM.
I noticed yesterday that this was happening when I hit the brakes!
Does anyone know if it is the brake light switch that could cause this problem?

 

I'm still having problems with the ASR light coming on and going into LHM.
I noticed yesterday that this was happening when I hit the brakes!
Does anyone know if it is the brake light switch that could cause this problem?

Pretty cheap and easy to change, you can then progress to the neutral safety switch if the problem continues.

 

James,

In a Mercedes everything is possible.

My thought is a short.

My theory.

The brake switch, sends a ground signal to disengage the cruise control, from there to the throttle actuator....

Actuator goes limp, like a noodle.

See where I am going?

Regards,
aam.

 

James,


Actuator goes limp, like a noodle.

See where I am going?

Regards,
aam.

Absolutely

It would seem like the fix is pretty straightforward but with with all I've got going on here (not at all bad things) I'll have to put the fix on the back-burner for a few days.

I've still got the '98 SL500 pano and the 2005 Ml to run around in :thumbsup:

 

Here is why this forum is the ideal place for Sl500 owners. We began having the ABS - BAS - No cruise control issue. I figured maybe someone else had experienced this problem.
Sure enough, the answer was here alright, even 7 years later! Thank you for keeping the forum alive!!!

 

IIRC you have to be a contortionist to reach it but sooner or later they need to be replaced. Such a simple part that can show such perplexing symptoms

 

wlb50,

I have 98 SL and It appears my brake light switch has gone bad. I blew fuse #10 twice after replacing it and tapping on the brakes to put the car in drive. All the gauges go out right after tapping the brakes and the fuse blows. My scan tool said P1584 error code (stop lamp switch). How do I remove the panel under the dash? I did remove 2 (8 or 10 mil screws) and the plastic nut at the back but I can't seem to figure out how to remove the panel. Any tips would be appreciated.

 

There are 3 screws on the top of the panel, one is below parking brake release lever one is in the middle left of the steering wheel and the other to the right of it ..... it should drop down after the 3 are removed. You may have to pull the parking brake release handle out a bit to access the left side screw.

 

I changed the brake light switch yesterday on my R129 SL280/320 -97. Removed 3 Philips screws( as mentioned one is hiding below parking brake release lever) and 2 x 8mm bolt head screws to remove the upholstery panel under the dash. That was the easy part...its very tight of space and difficult to get a hand in there... Was able to remove the bigger electric connector but gave up on the smaller one, no way without braking something. Decided to remove the whole switch first. Turn it 90 degrees right pressing the clip simultaneously and off it goes, later easy to remove the remaining connector afterwards. New oem switch(part A0015450109), checked the moving part was fully extended, connected both wire connectors and somehow fitted it in the slot turning 90 degrees left it snapped in place. Did not reset anything, everything worked fine on test drive so consider it a success. Febi Bilstein part about 10 euros, oem 42... this time went with the original, looks very similar though.

 

Hi all

My dad has picked up a '97 SL500 and we've had the ABS and ESP light come on. Ran diags and error codes pointed to the brake light switch. We've replaced the switch however we're still getting the dash lights when the new part has been installed. We then tried the new part without fitting to the brake pedal assembly and the dash lights would disappear.

I have noticed that when the brake light switch is being mounted into the pedal assembly the white plunger gets pushed into a small piece of metal, which I'm assuming is how the switch interacts with the brake pedal. My assumption was that the small piece of metal would only touch the plunger when the brake pedal is pressed down causing the brake lights to switch on? is it possible that the brake pedal is too far forward? I should note that the car has been sat for a few years with the prev owner, but they have recently changed the battery and brake pads (unsure whether they carried out brake fluid change)

When the switch is fitted the plunger is pushed down so much that it lock into place, causing the brake lights to be on at all times.

Not an expert at this by any means and hope someone can point us in the right direction, I have no doubt we're missing something very simple.

Thanks.

 

Hi all

My dad has picked up a '97 SL500 and we've had the ABS and ESP light come on. Ran diags and error codes pointed to the brake light switch. We've replaced the switch however we're still getting the dash lights when the new part has been installed. We then tried the new part without fitting to the brake pedal assembly and the dash lights would disappear.

I have noticed that when the brake light switch is being mounted into the pedal assembly the white plunger gets pushed into a small piece of metal, which I'm assuming is how the switch interacts with the brake pedal. My assumption was that the small piece of metal would only touch the plunger when the brake pedal is pressed down causing the brake lights to switch on? is it possible that the brake pedal is too far forward? I should note that the car has been sat for a few years with the prev owner, but they have recently changed the battery and brake pads (unsure whether they carried out brake fluid change)

When the switch is fitted the plunger is pushed down so much that it lock into place, causing the brake lights to be on at all times.

Not an expert at this by any means and hope someone can point us in the right direction, I have no doubt we're missing something very simple.

Thanks.

This is fresh in my mind as I just changed mine a few days ago. When I first put it in all my brake lights were constantly illuminated. I pressed and depressed the brake pedal a few times and the switch actually came off. I guess it wasn’t seated all the way in? There is a snap that has to occur and it took a good amount of force. Another thing to look at is to ensure the white plunger is fully out when you put the switch in place

 

Agree on above statement, it seams very important based on various instructions to ensure the plunger is fully out when you put the switch in place.

 

Hi,

An update on my car. Took on a long drive after fitting the new brake light switch and lights on dash still on. I've since bought a new brake light switch from Febi Bilstein and unfortunately no luck again.

I checked the Brake Pressure Sensor on my diagnostic tool and it was showing 82 bar. When the brake pedal is pressed it will go down to 11 bar and under.

From watching some YouTube videos it could potentially be the brake master cylinder? I'll keep doing some research and report back.

Thanks

 

I had one year a go also the BAS-EPS light coming on. I pulled and put back all fuses/relays that was able to find, then adjusted tire pressure as per owners manual( different pressure on front and rear axle). Next morning no lights, and remained the same for almost a year. Not sure what the cure was. Then I got the break switch code and changed that, all good now.

 

thanks for sharing,

I've since corrected the tyre pressures (very low) and have checked the fuses. I noticed that a total of 8 fuses were corroded like this one.

I've ordered new fuses and will replace, I'll also take a look at the relays today.

Thanks

EDIT: fuses were all live after testing with multimeter.