1978 124-Ignition switch & starter & solenoid all tested good. Problem is the Ignition switch red wire(to solenoid) should not be hot until key is turned to start car. It is hot all the time??? Why is this?
The switch red terminal tests fine for current when key is turned to start. Help please

Update to my last thread on the starter issue. BTW all wiring is per 1978 American 124: starter wired with Black & brown wires to starter right solenoid post along with battery cable, red wire (from ignition) to solenoid middle elec.connecter blade, and left side solenoid is connected to starter (directly down into starter & connected at solenoid post). It matches wire diagram but I must be doing something wrong. ?? no start

I'm not familiar with the 124 Spider, but am very familiar with the 124 Sport Coupe, however I believe these 2 models are nearly identical, mechanically and electrically, so....

The red wire from the ignition switch to the starter solenoid should only be live (i.e. 'hot') when the key is turned to the start position.

Are you sure this red wire is connected to the correct terminal on the rear of the ignition switch? Iirc, it should go to the terminal marked '50'.

Also, iirc the bunch of cables that connect to the rear of the ignition switch are covered by a plastic boot/cover. When pulling back this boot/cover, it's important that the loom/bunch of cables is held and the boot/cover is eased back. I've seen it happen that some of the cables can be slightly pulled (i.e. not completely disconnected) from their terminals on the rear of the ignition switch, enough that one of more cables can make contact with another cable, thereby becoming 'hot' at the wrong time. It's worth checking that each cable terminal is tight on it's connection, I've sometimes had to tighten the terminals by squeezing gently with a pair of pliers, to ensure a good connection.

If all the cables are correctly connected at the rear of the ignition switch and no cables are touching, then if terminal '50' is live without the key being turned to the 'start' position, then surely the ignition switch is faulty (perhaps shorted internally)? (despite your tests - you didn't say how you tested the ignition switch, starter motor and solenoid). I've seen one or 2 ignition switches which had melted internally, but this usually resulted in failure to make a contact at the appropriate key position.

In general, for the starter motor to work, you need a power feed from a (well-charged) battery to the starter motor main terminal, the starter motor/engine to be earthed/grounded back to the battery, and power to be applied to the small blade terminal on the starter solenoid.

Maybe try disconnecting the thin red wire from the solenoid and connect a separate jumper cable from the solenoid blade terminal directly to the battery positive terminal? If the starter motor now spins-over the engine, at least you'll now know that the starter motor, solenoid, battery, battery cables and grounds are ok. The problem then is most likely to be the ignition switch or that red cable.

Hth,

Al.

Thks for input. I tested starter & solenoid(new solenoid) before installing starter. ALso ignition tested with tester and red is to correct 50 pin. It works when key is turned to start.
I will try your starter battery post to solenoid middle terminal blade. This is a strange problem. BTY ignition switch is new.
My biggest problem is when red wire at switch is connected to the switch, it's hot. This should not be hot. THEN when I disconnect red wire from ignition switch, I test switch and red works fiine as it should.

Why? It has worked fine a week ago so maybe there is short somewhere.

So.... The starter is new and worked ok when tested before installation.

The ignition switch is new and tested ok using a meter, i.e. terminal 50 on the ignition switch is only 'hot' when the key is turned to the start position.

But the red wire is hot when connected to ignition switch terminal 50?

Have you tested if the red wire is hot before you connect it to the ign. switch? (it shouldn't be).

That red wire, if hot, should cause the starter motor to operate, the same as it would if you turned the ign. key to start.

Maybe there's a short between the red wire and another normally hot wire somewhere along the line, resulting in the red wire being hot when it shouldn't be?

Could you be confusing the red wire and the pink wires at the ignition switch?

Your earlier thread about this problem mentioned it all started after you connected the battery terminals the wrong way around? All this should have done is blow some of the diodes in the alternator rectifier - however shorted diodes can result in the battery self-discharging via the alternator field windings? (iirc) to ground. Someone previously suggested disconnecting the alternator before trying to start the car - have you tried this?

You also mentioned that some wire or other had burned out and you replaced it? I'd suggest you carefully check all cables that that burned wire might have been in contact with/alongside/crossed-over, maybe it damaged the insulation somewhere on the 'red' wire, allowing it to touch a 'hot' wire?

But why the starter motor isn't trying to run all the time if the red wire is hot is confusing. Maybe the red wire is hot because it's touching a hot wire somewhere, sufficient to light a test-lamp or indicate on a meter but not making sufficient contact to flow enough current to operate the solenoid and cause the starter motor to turn? But there again, when the key is turned to 'start' on the new ignition switch, sufficient power should flow down the red wire to operate the solenoid etc.

Don't forget to double-check the battery post connections, battery ground lead to body and the engine to body ground lead (iirc, this is fitted between the transmission bellhousing and body under the car) and ensure the battery is in a good state of charge.

Hth,

Al.

Thanks for input. I just tested wires again today and the solenoid terminal is hot. THis confuses me. When testing ignition switch obviously red wire is hot all the time. Just as you stated it should not be. My solenoid is new and tested before installing.
So what I did 2 wks ago is bench test my old solenoid to see if the terminal was hot when I connected 12V to battery post side of solenoid. It tested hot as well.
I agree with you, this should not be hot because the switch send current to the terminal to kick in bendix and turn starter.
Not sure what problem is. I was thinking switch but I tested it.

I just put this starter issue to bed. Found lead from starter motor to solenoid on wrong side of solenoid. Works great now

Glad you figured it out.