Mercedes: brakes (antilock system), mercedes benz 300sd, number search results

Question
I have a 1985 300SD turbo diesel, and about a week ago I put the car throug one of these car wash that spray high pressure water under the carriage and since then the light keep showing on the instrument panel(antilock lighth) what I need some one to point in the correct direction on what to check to troubled shoot the problem.
I did check the sensora at the front wheels and they look clean so I do not know any other place to check maybe one of you guys can help.
Also I had notice that when I jus started the car and if I hit a little bump the lighth shows inmediately, so it may a loose wire but were.
Please help... Thanks

Answer
If you are lucky.
Remove both front wheel bearing hubs.
Clean the sensor tip and sensor ring teeth then reinstall.

Worst case:
Bad front wheel sensor.
If the sensors are bad, suggest you subscribe to alldatadiy.com for the service information with graphics that you will need.

PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1985 Mercedes Benz 300SD
Part: ABS Speed Sensor
 Note:  Front - Left
Up to chassis A-514906, requires (1) 126 540 81 07 cable and (1) 126 546 42 43 bracket.     
N6030-70589 ABS Speed Sensor Bosch IN STOCK $146.02  
http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=merc...   

PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1985 Mercedes Benz 300SD
Part: ABS Speed Sensor
 Note:  Front - Right
Up to chassis A-514906, requires (1) 126 540 81 07 cable and (1) 126 546 42 43 bracket.     
N6030-70588 ABS Speed Sensor Bosch IN STOCK $146.02  
http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=merc...