500 sl electrical problems help please

[ezelife]

Hi guys just bought 500sl but have few issues

The car is 1991

Car rides ridiculously hard and the suspension light and abs light is on

I have checked ovp fuse and both fuses look fine

I have suspicion the roof doesnt work either but hardtop is attached so if someone could advise on procedure for removing hardtop I would be able to check

The car has recently had new battery as was in storage for 6 months hence why I checked ovp but no luck

Any help would be greatly appreciatted thanks

 

[BTB 500]

'Suspension light' presumably means the car has ADS (adaptive damping). In which case hard ride will almost certainly mean the accumulators (spheres) are shot and need replacing.

Low voltage can throw up all sorts of errors/faults including roof and ABS problems. With later cars you need to get the faults read/cleared on a STAR computer ... not sure what the process is for earlier cars. Hopefully someone will chime in.

Have you got a handbook? To unlock the hard top you just operate the roof switch. I know for later cars both doors have to be open, which catches people out.

 

[Taliesyn]

I had this problem with my 500SL about 10 years ago, the hard ride is a good indicator of a problem with either the pump or the spheres, providing fluid level is ok.
I have the same warning light on again and have had the system completely checked twice and no fault can be found, so I've been told it's a control unit problem, they're not cheap, so I'm living with the light as the suspension is functioning fine (Passed two MOT's)
That said the repairs I had done 10 years ago were around £1800.

 

[Taliesyn]

Here's a link to how to remove the hard top.
R129 Mercedes Benz 280, 320, 500, 600 SL Class Removable Roof Electric Opening - YouTube

 

[Taliesyn]

Just remembered that the warning light will also stay on once the engine is started if the battery has been disconnected. So what you should also try is to start the engine, turn steering wheel from lock to lock and back to centre position.

 

[moakesr]

Check the level of the hydraulic fluid in the suspension reservoir, if it has dropped then most likely one or more spheres have failed. On a 1991 car you will need a blink code reader to find out exactly why the ADS suspension warning light is on, and apart from the steering wheel lock to lock for battery reset, all other codes will require the reader to reset.