SweetChariots

I have a 2004 ML 350 with a BAS light on from the day I bought it for my wife over a year ago... Funds have been crazy tight and since it hasn't been a performance or safety issue that I know of, I've let it go...

But NOW we'd like to at least LOCATE the switch that could trip this Light & Error... I don't have the code in front of me, but it said it was a switch and I wonder if its the basic light switch, or a switch that would tell the computer that something is wrong...

If anyone has any input, let me know... VIN is 4JGAB57E04A467833 Thanks!

Plutoe

Typically located in the upper section of the brake pedal assy, therefore look up!!

Maj. Dundee

As of model year 2003, M/B eliminated the Brake Light Sw. at the brake pedal. Everything now is controlled by the Brake Booster.

Do your brake lights illuminate when you step of the pedal?

What is the code number?

SweetChariots

Yes, lights are working good... I see 2 sensor/switches on booster... one is for BAS Diaphram position and maybe the other is lights... There is an INTERNAL switch though, and THAT was what I was wondering about as well... I have not connected Star Diagnostics up to it yet, so I don't have the code #, but my wife had it checked and I can't find her print out with results, codes, etc...

Will get to it, just handling so many other projects and my father's health is declining... Multi-tasking BIG time... This is a 2004 ML 350 with about 110k on it... runs very good, from Florida... Solid... I wonder if it was in a hard braking situation at one time and may have tripped the internal switch in the Master Cylinder.

I also have a Front Cooling Fan Module or relay issue... When using AC, radiator electric fans come on & do well to cool, but after shutting off vehicle there have been a couple times the fans WON'T shut off, so I unplugged the harness because the battery was run flat 1 time before... Recently, they ran for 1/2 hour & shut off...

That is another project & with my wife & I living in 2 homes and me traveling for my dad and other business I haven't got to the Fan Relay or Module... What ever controls it... I have NOT been able to locate the relay yet... I suspect its hanging up, or the temp trip sensor may be staying on....

Maj. Dundee

If your brake lights are working then there is another problem.

The outside components on the Brake Booster have nothing to do with actuating the brake lights. Brake Lights are actuated by the internal Brake Release Sw. (A7/7s1) and cannot be replaced. A used or new Brake Booster must be installed.

I would help you greatly if you posted the code/s that are sored.

SweetChariots

The problem is on the Dashboard... The BAS light is on & one other & they are right next to each other and I was told it was a switch and the printout from a scan I can't locate right now... I'm off site and don't have access to the vehicle to run a scan... My father is dying & I am living with him & currently working on a 1995 S50 Coupe... tough situation... So, when I can get a scan I'll be sure to post the code.. Glad to hear the internal mast cylinder switch does the lights... They work...

Maj. Dundee

You will still have to have the codes read, namely "C" codes.