92 SL500 ASR& ABS lights come on when vehicle is moved not when started ,but as soon as brakes are applied. The engine is OK and will tach out, manual says 50% power if malfunction.
Ever heard of a problem like this? Occasionally the light switch will do funny things, right marker light has come on front and rear.
You sound like you have many problems.
The first thing you should do is get someone to scan the computer system for any trouble codes. Repair any trouble codes that may come up.
The anti lock brakes have many sensors and solenoids, the only way to find the location of the problem is to use a scanner.
One thing you can check is the charging voltage. When the charging voltage is low it may cause some electronic systems to shut down until the voltage is restored to its proper operating range, and it also may be causing strange things to happen with the lights.
Making sure the Battery and its cables are clean of all corrosion and make sure all body grounds are clean and tight.
If you don't know anyone with a scanner you can go to your local AutoZone Auto Parts Store and they will usually scan your car for free.