92 Trans Sport, 3800, odd electrical problem

This happened last weekend once, and has done it several times since then. The van runs and drives beautifully, and everything works.

Except several times when it is started (cold or warm, does not matter), I get a SES light. The power windows are dead. The heater blower is dead. The transmission solenoids will not activate (I put it in gear and it acts like it is almost out of fluid, and the fluid is fine). The radio works. The power locks work. The engine starts, runs, and revs perfectly normal. I asked the wife to check some other accessories to see what else works and doesnt work when it does this.

It only does it at startup, never when it was already running. Shut it off and restart it, and it is usually fine. But sometimes it takes a few times of restarting it to make the problem go away. Everything is consistent, it is one problem. Once I get a successful restart, everything immediately works perfectly and it drives and shifts perfectly like nothing ever happened.

When I check the codes, I get a code 21 (TPS high voltage) and code 56 (quad driver B).

In the past, about every 1000 miles or so, I have gotten a code 21 while driving, the cruise would drop out and the SES light would come on. Then it would go off and the cruise would work fine again. So the code 21 may be from that. It did it once the other day.

I went to check out the ECM, and I see whatever supports it at the bottom was broken off (and had been probably for years by the looks of it) so it was supported by the floorboard. I checked for loose connectors, and nothing was loose, but I reseated them all anyway. Yesterday it was fine. Today it acted up once.

Could a loose ECM connector do all this? Or is it most likely something else? I know the quad driver powers the transmission solenoids, but how about the power windows and heater blower? I have a factory service manual, but I am stumped at what it could be that is causing this. It is perfectly consistent. When it acts up, all 3 things always wont work (heater blower, trans solenoids, and power windows).

Any other ideas? Any other wiring I should be looking at?

I appear to have found the problem. Someone from another board suggested that all the things that are cutting out are high-load items that would be disabled during cranking, so the ignition switch may be bad. The manual shows all the circuits that were cutting out exclusively on the RUN terminal of the ignition switch.

I checked the ignition switch and the RUN terminal was melted. I replaced the switch and during several starts it seems to work fine. Not sure why it got melted in the first place, Ill have to keep an eye on things.

If it acts up again Ill post again.