Hi Guys, can any body tell me what powers the fuse box is it a relay or some other power source. Thanks in advance. Ed.

 

the battery has a + cable which goes to the starter, another wire goes from starter picks up alternator and goes to the "jump start post" under the hood right side near radiator. Then wires go to the fuse and relay board and ignition switch....more or less
However the battery ground strap from the - post goes to a wingnut bolt that screws into the chassis behind the tool kit in the rear of the car. Often the ground strap is corroded inside and does not flow power. Also if you mention the problem you are having there are some very helpful people who might be able to help. Like if the car will not crank or dash lights will not come on......might be a bad ignition switch.

 

Hi Jim, sorry i didnt tell you the problem is with my wifes car, witch is a mercedes C240 2002 model. i was checking the fuses with circuit tester powered by a regulated power supply when this happened, so i thought i blew a relay. after that i got a fault code whitch says (tele aid) and restraint system and visit shop witch means go to dealer witch i dont wanna do, if any one with trouble shooting exprience can help please do so. Thanks in advance. Ed.

 

Sorry, I know nothing about Mercedes.....

 

Not suprisingly not all cars are exactly the same - you can't assume anything based on how a 928 is wired - they are actually fairly unlike most other cars... due to the rear battery configuration.

Alan

 

try www.mercedesshop.com, forum for your model....
jp 83 Euro S AT 54k