Daughter in college loves her 1990 240 wagon, automatic, 258,000 miles, have had for 1 yr. Prev owner had ignition switch problem of some kind and bypassed part of the ignition. His mech put in a push button to start the car. Turn the key and push button. (I suspect that wiring runs from fuse to push button to starter)
Has run fine until yesterday. Daughter called, car died at work (70 miles away) and won't restart. I happened to be nearby today with limited tools, fuse for fuel is good, replaced fuel pump relay pump runs, spun fuses , no crank, no sound nothing. I also dismantled the push button and tried to start by touching the wires together, no luck no sound.
Tomorrow I'll head back with Bentley in hand, flywheel sensor and power amplifier, will check heat sink condition and will check for spark and voltage. Is there any way to jump the starter, big screwdriver??
I just want to drive it home. Any advice appreciated.

Run a length of insulated wire from the positive battery post to the starter solenoid. Starter should engage when 12v is applied to the solenoid. This will not be enough to make it run if the ignition switch is not enabling the ignition circuit.

With the previous owners jury rig of the ignition switch I would suspect additional problems there. I can not tell you how to bypass that switch to assure that the ignition circuit is getting the needed electrons to allow the engine to actually run.

Hopefully you know how to do that or someone will jump in and provide the needed information.

Good luck
Randy

Bring a small length of broom handle to hit the starter solenoid. Don't forget 36" of 1/2 extensions in case you need to replace the starter.
Make sure all grounds and battery leads are clean and solid. Bring a voltmeter and check for 12 volts and yes you can short the leads on the solenoid.
Dan