azbawood

hello all, i have an 02 c320 which all of the sudden just stopped cranking, stopped sending spark. locks and doors, lights, radio, everything working fine except for these issues. the starter relay is fine. i am not receiving the ground signal to the coil side of the starter relay. when i leave the key on and jump the relay it cranks just fine but has no spark anyone?
....also fuse 52 is fine and has been changed to 20amp. i know this problem has been discussed before on this forum, however i felt my case was a little more specific since it is not a fuse or relay issue, thanx in advance for the help

Glyn M Ruck

Check start enable fuses 31 & 57 as well

Moviela

Use a volt meter on the brown wires exiting the front SAM. If the voltage measured between the negative terminal on the battery and the brown wires in the SAM is more than .100 volt you have a loose connection there.

azbawood

All fuses and front sam have been checked and are ok. Sorry, forgot to mention that. As for the cables i will check asap. I'm starting to lean towards bad eis

Glyn M Ruck

EIS is certainly a possibility.

azbawood

,,,are these the ones you are talking about?? just check only the brown ones???...also, should this be a key on test or key off test?

Moviela

Yes, any brown wire is connected to chassis. Key on or off does not matter. The battery neg cable, the engine to chassis cable and the chassis ground post near the front SAM are suspects. Also the connections to the SAM could be dicey too. Look for good clean connections without any corrosion (green fuzz) and the connection is tight.

azbawood

ok, i'm assuming you mean check resistance? Since there will be no voltage when checking a ground with one lead on the cable and one lead on the neg. bat. terminal, or did I miss something?