Idling Switch Wiring

[mBdrvr]

There is no wiring in the wiring harness on the 250SE I'm putting back together for the idling switch.

The idling switch is p/n 000 545 24 04 and #51 in group 7 in the M129 parts book.

I'm attaching a picture.

I can't find anything on this part referenced anywhere.

Any help with the correct wiring to this switch would be appreciated.

Thanks,
Paul

[rgafitanu@gmail.com]

One terminal goes to the ground and the other one goes to the transmission modulator double solenoid. I believe it goes to the middle connector on the side of the transmission (could be brown with a white stripe but I am not sure). You will find it in the BBB or technical manual.
Radu

[mBdrvr]

Thanks for the information.

[wwheeler]

I have three different versions of the same thing. Not totally helpful but gets you started. MY US 280SE is more like the like the first two. My switches have power feeding from#3 and then to the two positions of the solenoid. The solenoid gets its own ground. That is contradictory to the third diagram, but that is the way it is wired on my car and is original. I checked twice myself to be sure.

The first diagram shows (4) positions on the terminal block. Mine only has three and the pressure switches/throttle solenoid are connected elsewhere.

[rgafitanu@gmail.com]

Interesting, my US 250SE is wired like the third. The difference is the location of the switches, on yours they are on the + line coming to the solenoid, on mine they are on the ground - line coming from the solenoid.

Radu

[wwheeler]

I don't get it either. And the two that are like mine are titled for 113 SL and many on this site say that theirs is only like the third also. It seems like I am the only one with positive wired switches. I thought I was going crazy until I saw the first two diagrams. The third comes from Sun Valley transmission rebuilders in the US. Not sure what their company name is today.

One day when I am back down there, I will test it yet again. The last time I tested it, I had all the wires disconnected so that there would be no back feed. It was totally conclusive that the switches were + fed.

[rgafitanu@gmail.com]

I forgot to say that my 250SE had the engine swapped with a 230 and that can come only from an SL so maybe it adopted that wiring. Like you I always tested the components disconnected so I cannot be sure. I remember that I had to fiddle with it to make it work but I never checked the direction the current is flowing and the wire colors are faded so I cannot find a solid brown coming to the idle switch. I didn't pay too much attention to the difference. It could have been one of those US NHTSA rules that the switch should be upstream of the load.