R129 srs light?

[Sdemon]

Dear all

Unfortunately my srs light came on after turning the car on which had been sitting dormant for some time with a flat battery.

Car is a 500sl 93 model

I have read the causes for this light to come on including faulty airbag sensor, short in the wires in the seat etc.

My question is that, the light dims and then becomes strong, never flickers. Is there an area in the engine bay which could explain this? Perhaps a damaged wire which is in its way out or something? I do know that my starter harness under the car is looking quite bad and will need a refurb.

Some also say to examine the fuses/ relays in the engine bay but not sure which one that would be.

Any help would be great.

Many thanks

 

[Blobcat]

Fit a fully charged battery drive slowly forward and turn the steering wheel from lock to lock and you might find the warning goes away

 

[Sdemon]

Many thanks for the reply

I have done that, fully charged, drove, turned steering wheel full locks and unfortunately it didn’t work

Seems a bit odd that it’s lightly lit and then brightens up. Makes me think that there is a loose faulty connection.

I have lifted the seats up to look for any loose connections and did not see any. The srs seat sensors I believe are apparently under the carpet which I have not yet investigated.

Any further ideas, perhaps a dodgy fuse/ relay which I could examine or clean up.

Many thanks

 

[LostKiwi]

Trying to remember....
Seat belt buckle switch is a possibility. Other than that in a 93 you only have a driver's airbag and possibly passenger one if it was optioned.

All you can do is trace wiring squirting every connection with contact cleaner (don't use WD-40!) or put it on diags to read the codes. A simple blink code reader should suffice for code reading..

 

[Sdemon]

Many thanks for your reply.

I think it might have to be fault code read.

Any other help is appreciated.

 

[LostKiwi]

If you have a glovebox in front of the passenger you don't have a passenger airbag. If you don't you do.

Download a files called cs1000.pdf - it gives a list of codes, pins to check and models. Makes sure you use the information for your model or you'll get a bad steer.

Blink code reader can be easily built - loads of info on Google. Fundamentally it's a switch, some wire, a resistor and an LED. Stick it in a box and you're away. The SRS module is pin 30.
1993 was a changeover year so it may also be digital in which case a blink code reader may not work. In that case you'll need Star or Carsoft PC based diagnostic software.

Note: an ODD2 reader will not work, even with an adapter.

 

[Sdemon]

Many thanks again for your help.

Os there any way of knowing if mine is a digital version?

 

[LostKiwi]

Only by testing.

 

[Sdemon]

Thanks for your advice.

Read the codes and it came with:

3,4,8,9

Drivers airbag squib
Passenger airbag squib
Voltage interrupted
Srs lamp

Was able to reset all. Perhaps the dead battery was the cause

Thanks again