My wife's 92 940, B230F, Rex Regina has started to display some odd symptoms, and I need any suggestions as where to look for the problem.

Sometimes as she's driving along, the engine will stall....dash lights illuminate....brakes and power steering become hard.

It will re-start itself (so far) before she comes to a stop, and continue on until the next "event".

I was thinking fuel pump relay until I heard (and saw) the next symptom.

The A/C clutch won't engage when the car is having this problem.
If she's driving along with the dash lights going on and off randomly, and the engine stalling (sometimes, not every time), the A/C pump is not running, although the switch is calling for cooling, and then, suddenly the A/C clutch will engage and start cooling the car.
When this happens, the dash lights will stop flickering and the car will perform perfectly until the next episode.

I don't have a electrical schematic for this car, but, it seems like there's a main relay somewhere thats failing.
I don't understand where the A/C clutch is connected to the dash lights and stalling issue.

In the past, I had a problem with the alternator not charging (dash light also not illuminating with the ignition switch on) that I traced back to a bad connection on the instrument cluster.
After I repaired the connection, it has performed well.
That was about 3 years ago.

This is a strange one to me.
Is there anywhere (on the web) where I can get the wiring schematic for this car?

Sorry for the long post.
Any help is appreciated.
thanks
steve