Nothing with the PNP realignment approach! disconnected brake light switch and shift solenoid switch, still no voltage from LIGHT GREEN back probing with switch plugged in, or any voltage at the BTSI fuse... What in the world tells this thing what gear it's in? The little line that lights up under the gears in the cluster doesn't light up for Park, Reverse, or Neutral... But the little line lights up for Drive... Is there any kind of bypass I can perform to get functions, therefore eliminating some options and further narrowing down my problem child? Don't mind replacing or fixing what's wrong, just need to know what the heck to replace!

 

UPDATE: I pulled the plugs going into the PNP switch and cleaned them and even bent the prongs over slightly on the PNP switch so when plugged up the prongs would make better contact... Now it's awoken most of the system. All of the gear indicators work in the cluster, the system now allows the shift solenoid to "click" and engage when stepping on the brake, which allows for proper shifting, but the transmission is not engaging in their respective gears. The shifter and indicator say it's in Reverse or Drive, 3, 2, and 1... But the damn thing just revs up like it's in Neutral! And the BTSI fuse still doesn't read proper voltage. I checked our other Trailblazer and it puts out a strong 12v reading at the BTSI fuse, this one does not... How can I be shifting it normally and get all the solenoids to click without the BTSI fuse getting any voltage? Maybe I just need to clean this PNP switch and connectors a little more!

 

This really getting a bit weird. I thought you installed a new PNP switch? Haven't had a chance to go back to the diagrams myself yet. Did you get access to them?

 

Yes, I did install a new PNP switch, but after it yielded the same systematic problems as before, I switched it back out with one of the 2 original ones, except I cleaned the heck out of the plug and the terminals on the PNP switch, scratched all that clear stuff out of there and out of the plugs and got most of the system to work... No, I didn't get access to schematics yet... Will be my next step if I can't figure out which input makes the LT GREEN wire hot, in turn sending voltage to the BTSI fuse... I believe you told me previously that it was one of the pinks... Sorry for the confusion, I've only got today off then I go back to work and I work 75-80 hrs a week.. scared this truck will fall victim to a time crisis! So I'm throwing Hail Marys and all at this!

 

J. There's a problem because the solenoids are not acting as they should. If there is no power at the BTSI fuse you should not be able to move the shift lever. The "Park Solenoid" requires power to unlock the shifter. Brake pedal position doesn't matter for this solenoid. It's purpose is to stay in locked position while the key is in the "Off" or "ACC" position. So if there in no power at the BTSI fuse (which feeds the solenoids), the solenoid would act as if the truck is off and stay in the locked position.

 

With the key in the off position, put your foot on the brake and see if you can shift,

 

Well now it gets even weirder... After going out and buying a can of electrical cleaner and thoroughly cleaning the plugs and re-inserting them I now have full voltage at the BTSI fuse, all the shift indicator lights are working for each respective gear that the shifter is placed in, truck warmed up and fluids are good (maybe a half quart over) and the transmission just revs in all the gears... I did put the bolts into the new torque converter and torqued them (seems to be common advise given to guys who just replaced a transmission and it won't go into gear) could there be one more wire not making connection that wouldn't give me power over the transmission? Correct me if I'm wrong, but if the transmission is shifted into park and it's actually in park (cannot move the truck) and then it's shifted in Neutral and I can push the tuck back and forth in the garage, then the transmission is installed properly right? And if the truck starts and runs without any clanking or whining, then the torque converter it installed properly right? Ahhhhhhhhhh! So sorry for bugging you, but I'm very mechanically inclined, been working on all my stuff for 20 years now but this is the first transmission I've put in post 1993 with all the neutral safety stuff! Relays, solenoids, fuses, safety switches... I miss my 69 step-side!

 

We can check for the right voltages for each range to see if that can give you a direction if you'd like. If you unplug C1 (the bottom plug on the PNP (the one with 4 wires)) you can see if the PNP is sending the correct signal ranges.

Pretty sure you can do this with C1 unplugged, but you need to leave C2 plugged in (the top one with 7 wires). Working at the PNP switch side, note which color wire corresponds with each pin. Then go through each shift range and check for HI/LOW voltage.

Pin A is for the BLK/WHT wire
Pin B is for the GRY wire
Pin C is for the WHT wire
Pin D is for the YEL wire

In Park KOEO you should see:

Pin A = LOW
Pin B = HI
Pin C = LOW
Pin D = HI

 

All 4 test the same... Around 11v, key in run, engine not running. Wondering which wire sends juice to the transmission pump... The level on the dipstick doesn't change. Cold, not running and warmed up and running shows the same level on the dipstick
​​​

 

OK, just to make sure we are taking the measurement correctly, plug C1 back in and check the voltages KOEO by back probing. If we get the same result, it will help point us the right way. Take measurements with shifter in DRIVE also.