All electronics dead except emergency flashers
 

As the title says the only thing on the car that functions are the emergency flashers. Nothing else responds at all. The battery is healthy and freshly charged, I have juice (only 9.5Volts?) at the ignition switch, a new ignition switch (and the old one tested out fine as well), and I've played with all kinds of grounds. I've added grounds from the motor to battery and from battery to chassis just trying to rule things out. I can't find any visible issues or broken wires. I've had a finicky coolant temp gauge for a while and I've also noticed that the wideband doesn't always want to start giving reading when the fog lights are on. If I would cycle the fog lights the wideband and fogs would both work great. The wideband is grounded with the radio... The harness in the car has obviously been altered in the past, but I have no idea why or how. Everything is nicely soldered and all the connections were then covered with heat shrink tubing. The car has run great for months and now its completely dead. It played possum once in June for about 20 minutes. Then as summer progressed the car would struggle to crank or not crank when it was warm, and now its a constant dead system.

Where are the grounds under the dash on an early 944? Why would potentially bad dash grounds lead to a no crank scenario? I really doubt that all the stock grounds suddenly failed together and that the addition of extra 4 gauge wire grounds isn't enough to at least get a power window or radio. Ideas?

Wiring harness issue?

Maybe, probably, but what issue gets juice to and through the ignition switch by nowhere else?

I know you say the battery is charged but have you checked it for 12 volts after turning on a high draw item like headlights, that the voltage is still near 12 volts and hasn't dropped to what you saw on the ignition switch? It's a quick check. I've had batteries that looked good with a voltmeter until I put a load on them and then the real condition reared it's ugly head.

I'll give the battery another load test to be sure, but I ran a jumper cable from it directly to the starter to see if it would crank and it did so I'm thinking the battery is probably in good shape. It almost has to be a failed ground(s)... I just don't know where.

Do you have a (bad) alternator-to-starter cable?

Maybe, but I would think the power windows and all the accessory electronics would still work. I don't get anything electrical on the car except the flashers. I'm hoping to get some work done on it tomorrow.

Problem solved, the power wire that feeds the ignition switch had a bad spot. Replacing it solved the problem.

Outstanding!!