Not the way I wanted to get home today!

The starter motor on my 240D is a week old and today a friend asked me to come and jump start his car. Sure, I said, and drove over to his house. I turned off my car for 3-4 minutes, then went to restart it and... nothing! No turning over, just nada.

I had a busy day ahead so didn't have time to look into it further, preferring to call breakdown service as I have a membership. Met the tow truck driver this evening who took a quick look and noticed this starter connection not fitted to anything:



Of course no tools were to hand to do anything about it!

Should this be connected to the starter too? I can't honestly remember from when I was working on it the other week, but maybe the mechanic who changed the starter missed it. I'm assuming it should be connected...

Thoughts?

Thanks

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Sold them all but I'll be back...

It sure looks like it is supposed to go there along with the Positive cable to the starter.

You of course can trace the wires or you can look this site someone posted for the wiring diagram: https://www.tonk.ca/models/w123/

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84 300D, 82 Volvo 244Gl Diesel

Ah thanks for the link. It's for the W123 though - mine is a W115, not sure if the wiring would be similar enough..!

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Sold them all but I'll be back...

Do an image search on 240D starter wires. If no success search on 300D starter wire.

I honestly don't see how it could go anywhere else.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

That "someone" was me. The links on the FSM site go by engine, so good chance same on your car. Good luck

Really, nobody here knows how to wire a starter?

The big fat wire is from the battery for the starter to draw from and is always hot. The small wires trigger the solenoid when you turn the key, so yes you need those hooked up.

Side note: If you have a terminal block on the passenger side wheel well, that's where those wires come out, which is where you can jump the terminals to bypass/diagnose a bad ignition switch.

OK, someone please 'splain me - how did the 240D start to drive over there in the first place?

The ring teminal was still loosely attached on the final start.
The fastener fell off during the drive.

Probably due to improber tightening (or a missing lock washer) during reassembly.

EDIT: IIRC, the 240 doesn't have a terminal block .

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Could I recommend something?

Install with a decent washer and don't use a lock/split washer. Lock washers don't hold up with vibration, they just back out.

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Onus probandi incumbit ei qui dicit, non ei qui negat

I recondition w123/w126/w124/w140/r107/r129/ steering boxes!


1984 300D "Elsa" odo reset 6/2011 147k
1983 300TD "Mitzi" ~268k OM603 powered
1995 E300 "Adelheid" 262k [Sold]

+1 on that. Those cables are pretty stiff and usually will retain their shape for quite awhile.

Also, heed the advice regarding not using a "lock" washer in an electrical connection. If you feel you must use a washer, use a "star" washer. It is self-defeating to ensure a solid connection and then use a lock washer which has a gap.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Just went out and reattached (on to the same connection peg as the other wire).

Still the same! Very confused now. It worked fine moments before yesterday morning and now not even a peep?!

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Sold them all but I'll be back...

Try moving the shift lever into the neutral position.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Two wires surely must go to different lugs on the solenoid.
The heavier lug is where the power from battery connects (B) (other wires may also connect there, because this is 12V direct from battery)
There is a second lug of same size that only connects solenoid to the motor. No wire connects to that. (M)
Another smaller lug is for the signal from the ignition switch that activates the solenoid which then connects the power from (B) to the starter. (S)

Your starter may be slightly different, but all starters work like this. If you measure voltage from B to ground (anywhere on engine) you should always have 12V. You should get 12V between S and ground when you turn the ignition switch to start position. As a test, you can use a big screwdriver or cable to short between B and M - starter should engage.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Using a VOM or test light, check for power to the small wire at the solenoid. It should get battery voltage when attempting to crank the motor. If power and no crank, problem is in starter/solenoid. If no power problem is elsewhere, let us know.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I looked at my '74 and those wires that were unattached on j-galap's car are attached to the starter's "B" terminal along with the big fat wire from the battery. Can't be any other way, really.

I took a look at the wiring diagram to see about those two wires connected to terminal B, the ones left hanging in j-galap's car. One goes to the B+ terminal on the alternator, and the other supplies power to fuse #1. Fuse #1 supplies power to numerous other circuits including trunk/interior lights, the combination switch for hazards, instrument cluster, and "steering lock". There's also a wire running to the rotary light switch that connects to the supply side of fuse #1 (un-fused connection?).

Seems like the lack of power to these circuits would have been noticeable, unless the ring terminal was touching the starter's B post good enough for everything to still work.

Could the battery in your car be dead, Mr. Galap, after jumping another vehicle? If the connection between the battery and the B+ terminal on the alternator were compromised perhaps the battery was not getting a good charge for the few days you ran the car after the starter installation.

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- Greg -
1973 220D, The Prodigal Benz
1974 240D