1994 SL500 (129) ASR problem
 

I have a problem with the ASR on my 129 SL500, basically, after starting the car, the light does not come on, only after a minute or so. But during that the time the light is not on, i can boot the car round corners and the ASR will prevent it from fishtailing. But when the light does come on, i can fishtail and do donuts to my hearts content!! There is no loss off power when the light does come on. But during the 1st minute, there is a humming sound coming from the rear of the car, sounds a bit like a pump running, but after the sound disappears the ASR light comes on. What could be causing this? Any help appreciated

Prit

humming sound from rear like pump running
 

Ah hah!!! The venerable vacuum pump up to its usual tricks again!!! I might be wrong, but this is a wild guess since I had this same problem of the humming or buzzing sound from the rear and nothing else in there can make any such sound except your 10 disc cd changer while it is changing discs???? The fuel pump is under the car and it fizzes or call it sizzles, doesn't hum. Points at some vacuum leaks elsewhere in the car. The pipes or tubes won't usually leak, but the rubber diaphrams do tear after much work and need replacement. My 2 cents worth. Forgive me if I'm on the wrong track, almost bedtime, rather already past bedtime thats why.

Where is the pump actually mounted (pics pls if you can), i'll jack the car up later and take a look at all the hoses

Cheers mate

Prit

humming sound from the boot
 

The vacuum pump on my C180 is situated behind the liner on the right side of the boot wall next to the petrol filler inlet. You can only see the pump if you pull off this liner. A few tubes come out of it to operate the door locks, the rearheadrest release and a few other things. The fuel pump/s is situated under the car near the right rear wheel on my car. Cheers.