I spent several hours chasing a "master warning light" on a Mercedes coupe. This one was a big red rectangular warning light in the middle of the dash with a big exclamation point on the lens- - - - -impossible to ignore! The wire powering the light had a particular color code that went everywhere- - - -under the dash, into the engine compartment, under the vehicle. etc. After about 6 hours of unwrapping wire looms and chasing circuits I discovered I could turn the light off by jacking up the front of the car about six inches. More troubleshooting with no results. I finally found a wire with the same color code leading into the top of the brake master cylinder- - - - -to a float valve.

ADDING TWO OUNCES OF BRAKE FLUID TURNED THE LIGHT OFF!

The car owner was a doctor who owned the local hospital, a really good customer who kept me busy maintaining six cars his family owned- - - - -he got a freebie that night, and I learned an expensive lesson!
Jerry

Last edited by Hotrod Lincoln; 06/12/2017 3:36 AM.
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!