My Caddy 2002 keeps stalling at different times. This last time (Saturday night) I was on the freeway in the middle of 10 lanes of traffic, dark and the car just died. No lights; no power, nothing. I managed to get to the side of the road and was able to restart it again. This has happened about 10 times in the last 5 years and I have paid to have it repaired about 4 times paying about 340 each time. At first they said it was sensors and now they say it is the ignition. Very frustrating and scarrie on the freeway.
One of the poles of the switch goes to the Power Trains Control module. It could be that as well. If push came to shove, you could tie a small 12V test bulb from where the ignition switch ties into the PTC. Put the light somewhere where you can see it but in your peripheral vision. Next time it stalls, see if the bulb goes out.
If so, the ignition switch may be at issue.
Else, maybe the PTC…
Here’s the wiring diagram of part of the ignition switch. The pole that the white wire attaches to is likely at fault because it likely runs the entire car, from ignition to fuel and including the dash lights that you say go out.