I tried to crank up my 300D turbo in my 240d today. All electrical seems to be 100 percent but it won't crank. So I went back to the switch that I had a lot of problems getting apart when I got the car and the ignition switch was really messed up. I had a heck of a job getting the loom out of the back of that old switch. Now I have a new lock and key, new ignition switch body, but I can't get the plug to lock up on this new one. I thought I had it locked in, but after it wouldn't crank, I went back and pulled on the plug in part in the rear of the ignition switch body and it came right out. Well, I will take it apart again and with the paper clip to hold the piece down, try to get it to lock. Any other ideas.

__________________
Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

Hi Jim,

Are you sure it will actually work?

By pass the whole starter system to test?

http://www.peachparts.com/shopforum/diesel-discussion/298080-stuck-storm-comming-how-directly-jump-starter-post2708674.html#post2708674

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Well I am sure it does not crank, and the 240D wiring does not have the little junction box to jump it from under the hood. Now my thinking is the starter function is eliminated because my harness is not locked to the switch body. Why? Is the problem in the switch body or the connector on the loom? Or am I not installing it correctly, I understand that it must be connected while the detent button is pushed down with a paper clip just like with installing the outer steel ring. I will go back and try to connect them.

__________________
Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

Make a junction block then.
Use an alligator clip lead on the solenoid (small wire terminal) and connect to batt +. It will crank.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Well yes, that would work. But Funola, that is not really the problem. The problem I think is in the ignition switch (or the harness end that connects to it) and is related to the fact that my harness connector does not seem able to lock up to the ignition switch. I have the little white circular thing in the back of the switch and it turns when I turn the key. But there is nothing I can see in the harness plug besides the 7 terminal posts and a rather large rectangular hole (opening). I had a real problem getting it apart and I wonder now if I broke it and a piece is missing. So I will continue searching. Let me know if you find something.

__________________
Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

I have two questions: This is on my W123, 240D with 7 post type plug.
1. How is that harness end locked into the body of the ignition switch?
2. If it is not locked in, but just plugged in, would everything work except the start function?

__________________
Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

Well you did say "the 240D wiring does not have the little junction box to jump it from under the hood" so I thought you have no way to get the car started so I thought of a way for you/

To get the keyed harness connector to pull out of the electrical ignition switch, you have to turn the key to the same position to remove the tumbler. If you don't do that, there's a chance of breaking something.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Not all the harnesses are locked in. I bought a new ignition switch assembly for the 84SD and it did not have the locking feature. From what I learned when switching out that assembly, the switch should work whether locked or not. All the locking assembly does is deter thieves by stopping them from pulling off the harness and jumping the terminals as far as I can tell.

It is locked via a T fitting which slides into the plastic end of the harness and turns to lock it in place.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13