ML320 - 1998 - ESP/BAS Dash Light - PeachParts Mercedes-Benz Forum

bbrewer · #1 10-25-2002, 10:46 PM

I just bought a 1998 ML320, and the ESP/BAS dash warning light is on anytime the ignition is turned on. Any ideas on how to correct this??
Thanks,

Gilly · #2 10-25-2002, 11:48 PM

You should post ML questions at the ML/GWagen/UNIMOG forum.
The light may be caused by a bad brakelight switch, been fairly common. Evem if the brakelights work fine, there is another set of contacts in the switch used by the ESP system.
Another possiblity is that the battery went dead or was disconnected and the steering angle sensor never got initialized. To do this, start the truck and turn the steering wheel fully left and fully right, do this a few times and see if the light goes out.

Gilly

bbrewer · #3 10-26-2002, 12:48 AM

Thanks Gilly.
From now on, I will only post in the ML area.
The brake lights work as expected, so where would I find that second set of contacts??

The battery DID lose a charge recently, from lack of use, but seems to work okay as long as it's driven every day.
I tried the steering wheel lock-to-lock procedure, but unless there is a trick to it, no change. :-(
Thank you for your quick response!!
Barry

Gilly · #4 10-26-2002, 09:35 AM

Barry:
Possibly you could try disconnecting the battery again, then try the lock to lock thing. You did do this several times, correct? You will also need to enter the radio code again if you do this, and set the clock and trip computer if you have one. Did you need to jump start when you lost power or did someone who knew this lock to lock thing needed to be done?
On the contacts for the brake pedal, both contacts are in the same switch, so if this would be the problem, you would just need the switch. I am unsure if just replacing the switch would force the light on the dash to go out though. Probably eventually it would, just not sure. I have the luxury at the dealership to just clear the code. It may be a good investment (unless the lock to lock thing clears it) to have the codes read out rather than buying something that won't fix it.

Gilly

bbrewer · #5 10-26-2002, 04:22 PM

I dis-connected the battery for about 15 minutes, re-connected it and then the FIRST thing I did was try the lock-to-lock procedure with the steering wheel. No change, light still on.
I'll pull the brake switch out next, but is there a way to test the switch before buying a new one??
Continuity?? Certain ohm reading?? Is it worth spraying some contact cleaner in to it, or is that going to do even MORE damage??

Thanks for all your help Gilly.

Gilly · #6 10-26-2002, 05:09 PM

There are 2 sets of pins on the brake light switch, one connector for each set (2 connectors). One set is normally open (infinite resistance) the other is normally closed (0 resistance) when the brake pedal is not applied.
When the pedal is applied, the opposite is true, the normally open switch is now 0 resistance, the normally closed switch is now open circuit (infinite resistance).
If you want to remove the switch, it works kind of like left ahnd threads: clockwise to remove, counter-clockwise to install.

Gilly

bbrewer · #7 10-27-2002, 03:51 PM

We're making progress, Gilly, although I think we're just finding out what works "right"...... :-)
Anyway, I tested the brake light switch, and it worked just as you said it should. So, what can I check next??

One thing I noticed is that along with the 4-wire connector to the brake-light switch, there is another 2-wire connector taped along side the 4-wire connector. It had an orange and brown wire, and it wasn't connected to anything. Is that correct??
Or did I just find the problem, although I don't see where it would connect to??

Thanks!!!

Gilly · #8 10-27-2002, 04:03 PM

Barry:
That's about all I can think of for you to check. Best next step is to have the fault memory read out and that'll narrow down your choices on what the problem is considerably.

Gilly