BAS ASR ABS warning lights only when headlights are turned on.

[Deleted member 57040]

1998 w210 E300 TD Estate

Hello all,
After checking the forums for a solution I found the brake light switch is a common cause of the BAS ASR light.

The BAS ASR and ABS warning lights come on but only when the headlights are turned on.

I have changed the brake light switch but that has not fixed it, so the clue to the problem is probably the fact that turning the headlights on cause the warning lights?

Anyone have experience with this?
Thanks in advance.

 

[Deleted member 57040]

Also, when the warning lights come on it can cause the steering to become stiffer and sometimes indicating right can stop the cruise control working and the speedo drops to zero. Hmmmm...

 

[BlackC55]

Check the earth on the osf just behind the headlamp. They often corrode and cause this exact fault.

Then get the fault codes read.

 

[Deleted member 57040]

Thank you for your input BlackC55, much appreciated. Will check on Monday.

 

[Deleted member 57040]

Check the earth on the osf just behind the headlamp. They often corrode and cause this exact fault.

Then get the fault codes read.

Thank you BlackC55, turns out it was indeed the earth behind the osf headlight. Took out the headlight, cleaned up the earth connections and reattached them, no more warning lights.

Glad I didn't believe the mechanic when he told me it was a problem with the gearbox...

 

[briseye]

ABS Warning Lights Come On When Headlights On

I have the same problem when I turn the headlights on. The ABS warning lights come on. I took out the offside headlamp (drivers side on the right) but I could not see the earth connection behind the headlamp. There was a single purple wire which plugs into the back of the headlamp which looks like an earth which disappeared towards the left hand side in front of the radiator. Can anyone tell me where exactly the earth connections are that I need to check and clean up?

 

[Deleted member 57040]

What fixed my problem was an earth wire that should of been attached to the body behind the headlight.

If you can post a photo of that general area I might be able to spot it for you.

 

[briseye]

Thanks, I will take a couple of photos when I get time in the next day or so and post it here.

 

[markjay]

This is likely to be result of low voltage.

Check the battery / alternator / earth etc.

 

[briseye]

The battery and alternator are both OK. Offside hedlamp and sidelight are dimmer than the nearside. Therefore I think it is an earth problem. I have attached 3 photos of the general area. Do you know roughly where the earth should be?

 

[Deleted member 57040]

I unscrewed and removed the whole headlight case which reveals the metal body underneath. In this area there was a wire with a screw on the end that was not attached to anything. I assumed this was an earth wire that had come loose so screwed it back into a hole in the metal body.

So if you take out the headlight, fingers crossed, you will see something similar.

 

[Big Eb]

Hello, had some work done. Tie rods and track rod ends. But when they couldn't loosen the old ones and after some heavy pulling and heat on old track rod end, started getting abs, asr, bas light come on at around 70mph, changed break switch today but hasn't cured problem, any ideas, thanks.