More Mercedes Electrical...
 

All wires are plugged. Kickdown worked before parking the car for two months. Now neither the kickdown works nor does the switch in the trans that does the same thing. In between parking it and starting it I had mucked about with some cables under the hood, but I'm pretty sure I got them all back in and the diagram doesn't point to any of the under-hood wiring anyways. Here's the wiring diagram. I can post up the wiring diagram of the fuel pump relay too if it'll help.

How to fix? Understand that electronics are magic as far as I'm concerned. As simple as this diagram is, this is extremely complex to me. I do have a multi-meter though. Can't say I know what to do with.

http://davidson.smugmug.com/photos/8...1_2hzGM-X3.jpg

Re: More Mercedes Electrical...
 

The solenoid gets power if either of the two switches is closed. Check to see if you have power at the switches (from the fuel pump relay according to the picture), and check to see if the switches are working. Check that the wiring has continuity to the solenoid.

That's about all the things you can check, because it's just two switches and a solenoid.

Re: More Mercedes Electrical...
 

Ok, see, like I said, electricity is magic to me. How do I check to see that the switches are working and have power? And that the wiring has continuity to the solenoid?

Re: More Mercedes Electrical...
 

Ok, there are no volts at the wire that goes to the switch. Now what?

Re: More Mercedes Electrical...
 

No volts? What happened to all your volts? Where did they go? :D


If it's the input side of the switch, from the fuel pump relay, I'd track towards the fuel pump relay and see if there is a wire break or something like that. It's obvious whether your fuel pump is working or not, so the problem is probably a corroded connection or a fatigued wire. Keep on troubleshooting.

Re: More Mercedes Electrical...
 

Well, the relay has different pins doing different jobs, so its possible for the fuel pump to work and the kickdown not.

Re: More Mercedes Electrical...
 

In case anybody is curious, it is apparently possibly for everything about the relay to work except the kickdown. It is now replaced and functional