Recently the ASR/BAS on our 99 C280 began to illuminate - I've narrowed it down to this:

PS: when it is on (the warning lamp) no cruise, when off cruise works fine

1. If I hold the brake HARD when starting it the light is off.

2. If I do not touch the brakes the light stays off.

3. If turning while braking lightly most of the time it lights up during a left turn

4. If turning while braking lightly it lights up up about 50% of the time on right turns

5. Maybe only once or twice out of ten stops will it light up if braking lightly while going straight

6. Hard brake applications seems to keep it unlit.... - but light cornering brake application more times then not lights up the light.....

Appears to come on not when you begin braking but as you release the pedal

OK, I'm thinking brake switch - but WHY? Thoughts? How exactly does this system work?

Can anyone list the variables for this warning lamp?

 

John:

Were you able to find out what was causing the problem? If so, how did you fix it?

 

It was a wiring harness near the ABS pump assembly - if you look just below it toward the front of the car you will find a retainer clip with a two-wire square connector with a fail-safe wire clip that MUST be popped fully on with an audible click.

Mine had shrunk with age (the wire's cover) and was straining against a small wire tie next to it - and the clip had worked itself loose.

Once I properly tightened the wire connection and worked some slack into the harness -to-body wire tie interface my ASR/ABS light went off and has stayed off for about 500 miles.

Now if I could just address the chronic 2ndary air system check engine light (intermittent) I'd be all set

 

JH: Thanks for the follow-up answer. I will take a look at the wiring harness to see if that is the problem with my BAS ASR/ABS lights. BTW, are you getting any codes on the "chronic 2ndary air system check engine light"?

 

I have the same problem. BAS light is on and cruise control does not work. Can someone tell me where the bas asr pump is located so that I can check the wire harness? Thank you so much, djedan.

 

Here is the connecter that pulled loose on my car. The assembly just to the right of it is the brake controller/pump assembly (or at least that's what I think it does).

The connection in question is the one in the center of the close-up picture, with the little wire clip on the side. On my car this connection had worked itself loose somehow.

 

Thanks, it worked on my second order of a brake switch. The first switch had
did not fit my plug. I noticed the the Part number was slightly different and reordered the part with the changed part number.

After I installed the new brake switch the light would still turn on and the cruise control did not work. I used WD40 on the switch handle and now it works like a charm.

 

What 'switch handle'? Could you give us a really detailed explanation or a picture? We better capture this fix for the forum.

I think I will lubricate mine just as maintenance... if you can help me find it!

 

With <switch handle>I meant to describethe drepressor (the part which moves in and out of the switch) that gets moved by the brake paddle when the brake is engaged (or disengaged when you remove your foot from the brake paddle).

I recommend that one should lubricate that `depressor` of the old part before ordering a replacement to see whether dust or dirt is the cause. I hope this explains the situation somewhat somewhat better, Dieter..

 

In the pictures below, The connector that popped off is your purge valve. you will get a check engine light with that unplugged. It has nothing to do with your braking system or bas/esp