300SD won't start unless terminal box is shorted
I picked up a ragged 1982 300SD over the weekend for a great price. However, the other morning I couldn't get it to start. The starter wasn't turning over, but the car had power and a good battery. I couldn't hear a starter solenoid click either. From my research online and owning a couple of W123s, I tried shorting the two outer terminals of the starter terminal box with the key in the run position and it immediately fired right up.
What part could be going bad? The starter is new from the prior owner, so the only other ideas I could think is that either the neutral safety switch is bad or the ignition switch on the rear of the ignition assembly is bad. Are there any other parts I might want to look at? If all else fails, I'll install a push button start in conjunction with the key, but preferably, I'd like to fix the problem. Thanks!