With respect, the ignition switch has multiple circuits and not all will fail. Have replaced many of these for this issue. Simular to loss of cruise control due to a bad brake switch and the brake lights work properly.

The ignition switch supplies batt to both the engine and trans module together. If one powers and the other does not the ignition switch is NOT the problem.

I thought the white wire is the problem , what could be more ?
if you saw in the switch electric draw , the white wire supply to the trans , I checked all the other (with bulb test) and it was OK

ignition switch connector terminal C1 white wire powers the trans fuse. terminal C5 pink wire powers ecm 1,ign 1,ign e, gauges, air bag, turn/back up. terminal D1 powers crank fuse. Different circuits out of the ign switch. owner said he jumped power from the pink wire to the white wire at the switch and it is operating as designed. Guess the fact that I have seen this issue many times not only on M/L vans but also on K series and */T series. Replacement of the ignition switch WAS the repair and they all would start and drive in with only 3rd and reverse with the 4l60E and 2nd and reverse with a 4l80e. Not going to argue only trying to help someone and only stating fact and the results of past experiences.

How many contacts in the switch for the run position. Not wires connected but the switch itself. One switch turns on multiple devises. I don't think there are three sets of contacts in the ignition switch for the run position.

And how many different circuits come out of the switch in the run position. More than one. Internal circuit fault with-in the switch. Again I have seen more than a few with this failure. was very COMMON to see. I guess your telling me that all those vehicles didn't get fixed. I guess GM is wrong also, see TSB 01-07-30-002E. Think again. This is the last I will comment on this issue.

https://blazerforum.com/forum/articl...-switch-33465/

And how many different circuits internal of the switch are there in the run position and how many come out of the switch? More than one. Like I stated - Internal Circuit failure with-in the switch. I have replaced many of these in not only M/L vans but */T series and C/K series also. I guess your telling me those vehicles were not repaired? You must think GM is wrong also, see TSB 01-07-30-002E. I Think your mistaken. This will be the last I comment on this subject.

This was an item I replaced when I purchased my 94 Fleetwood RV (P-30/32 chassis) back in Sept 2014. It can cause a slew of weird issue/*. Looked the OE one over real well and it did not show any overheating signs but haven replaced it added a nice comfortable feel of not having it pop up during a trip.