It began a few days ago when the shifter had to be put into Drive then back into Park to turn over, now it won't turn over at all. The neutral safety switch is almost brand new and was replaced with the transmission a few months ago.

The shifter can be moved anytime with the key on or off
If the shifter is moved with the key on, the key can't be removed unless it is in Park
It won't roll while in Park but does in Neutral
The dash display never moves from Park when the shifter is moved
The reverse lights do not illuminate when it's in Reverse
The wiring looks ok at the neutral switch
The battery is good- no action at all from the solenoid
The scanner communicates and shows no codes

 

Shift interlock at the shifter itself. Have to pull the handle (set screw on the back of the handle) and cupholder part off to get to it.

 

the cluster should show what gear you are in. does the shift cable move when changing gears? maybe the bushing on the shifter side of the cable is disconnected or bad.

 

can you see the live data stream with the scanner?

need to validate what the data is at the PCM and TCM if it has one

check for harness damage from the trans swap,

Neal

 

Thank you for the help-
I pulled the cupholder and wiggled the wires at the shift interlock but my cheapo digital manual doesn't show how to replace it. When I tried the key it started. The display still says it's in Park all the time and the shifter can be moved with no key in the ignition. It does move in forward and reverse.
My scanner is just a cheapo good for CEL and does connect, but not throwing any codes. The roof does leak because I haven't sealed the lights yet, and the floor board was wet the other day. I vacuumed the water and our humidity is at 25% now.
I'm going to take it to a mechanic for a complete scan next week, I just need to find a new one cause my usual one ripped me badly last time.
This stuff always happens with a full tank of gas and just after my wife drives it. LOL

 

Looks like someone already replaced the connector at the shifter interlock. Anyways I just poked in the GM eSI System. With your symptoms I would now guess it is something with the module on the transmission itself. Probably a broken wire, bad ground, or the range switch itself.

 

thats not the shift cable. you are looking for the other end of the cable that moves the neutral switch. the one that is connected to the transmission range selector arm.

 

Took it out for a spin and the dash gear indicator started working and everything else too. The shops are all taking appointments weeks from now just to run a diagnostics. I suspect something is getting wet or the speed sensor hooked to the non-stock radio is messing things up. The shift lever still moves anytime, but the button releases easier when the brake is applied.
Thank you to everyone for your help, I have the AAA platinum so I will just drive it till it throws a code or strands me. Still love my H2 though and my wife won't drive it anymore, so that's a win. LOL