Solenoid voltage
 

Problem: Engine not cranking when tuning key

Tests so far: 12.36 volts at battery and at 2 screws on right fender well. When jumping two screws(which closest to battery being one and the second screw) nothing happens. I also have 12.36 volts at larger wire on solenoid. But, no volts at smaller wire on solenoid either while key is off or while trying to turn ignition key.

Other: Cleaned both battery terminals and cables. Cleaned ground strap that attaches to transmission bell housing as well as the ground strap that attaches to the right fender well.

Question: Does this necessarily narrow problem to solenoid? Or is it still possible for it to be the NSS or possibly ignition switch? And is it necessary to remove small wire that attaches to solenoid to see if any voltage present at the wire itself while trying to turn the ignition switch?

Any help or ideas of possible solutions are really appreciated.

Thanks
Charlie

Anyone? I know that this is much discussed topic, and I have used the search as well as archives. Thanks in advance

Charlie

If there's no voltage to small wire, the solenoid doesn't do anything. Check your ignition switch.

If you want to test solenoid, short large and small wire. It'll crank, so be prepared for that.

KRGC,

It could also be a bad section in the starter. The current for the solomnoid pick coil goes thru the starter and is shunted out when the contacts in the solonoid close. Then the hold coil holds the solonoid in the start position until the key is released.

Thus if the starter is not conducting current, the solonoid will not work.

U could try shorting the wire between the starter and solonoid to see if the solonoid works. Note, only do this mometarially. If the solonoid still doesn't "kick in", most likely the solonoid is not working.

P E H

Update, I ran a wire from small wire on solenoid and then touched +terminal on battery and the starter turned the engine over.
So I can turn the ignition and activate glow plugs and then repeat above and start the car. Although a temporary fix, would love to get some input as to what may be the cause of this. Thanks again

Charlie

Either the wire from ignition switch to solenoid is cut at some point (rare) or ignition switch itself is broken. Both can be tested with multimeter, testing the wire requires longish measurement cables though.

KRGC,

I didn't see what model MB U have or if it is an auto transmission. If auto it could be the nuetral switch.

At least we know now that the starter and solonoid are OK.

P E H

P E H
She's a '85 300D automatic with 294k. I got her with 234k and this is the only trouble I've had. Eventually I'm going to learn how to put this useful info in my signature like the rest of ya'll as soon as I find out how.:book:

Thanks
Charlie

Charlie,

I have seen many posts here about the nuetral switch going bad causing the solonoid/starter not to work. Therefore, I would start by checking the nuetral switch

P E H