maybe the harness got pinched during install i've seen it happen between the bell housing and block area and on intake manifold installs. sometimes just moving harnesses around causes issues.

 

I found the 2 wires that control the motor on throttle body yellow and brown have no voltage traced it back to a pcm plug. I checkd for continuity from the throttle body to ecm plug and its good. So I checked for voltage on the pcm side there is 9v on those 2 pins however when I connect It all back up I got nothing I checked all grounds even made myself a new ground wire to test with. I have a harness that came with my motor hooked up that one pcm plug and I get 9v to the 2 wires on the throttle body I cant use this harness tho as they cut the wires and its slightly diffrent so I am stumped Lol.

 

check the pins they might loose fit or corrosion. you can de pin the harness to adjust or replace. bad connections can carry voltage so a multimeter will show voltages but it might not pass current try with a test light instead maybe. that will pull current.

 

Fired the parts cannon some more new ignition switch cause I noticed it was being janky and now the 0689 code is gone just have the p1682-00 ignition 1 switch circut 2. Giving this a couple more days of my time before I throw In the towel and put it up for sale I have never EVER had such a pile of over complicated trash lol. I have been all over this truck messing with connections ect Its a shame because its a real clean truck never owned one before I like how it looks but every time I buy something someone else took apart before me I get bit in the *** never again.

 

so if the spare harness is getting power properly to the throttle body then why not de-pin it from the spare harness and pin it into the existing one it sounds like you found your issue?

 

So the sapre harness even tho it shows 9v when I plug it in I cant confirm was from a hummer possibly a colorado so maybe its a smidge diffrent even tho it looks the same the pin is in same spot. But what I am confused about is according to what i have seen when in 'reduced power mode' throttle body stays at 30% home position so wouldnt there be no power going to it because its not being told to turn on... I have voltage at the 5v ref wires and the throttle position sensor appears to read Just nothing at the 2 wires that control the acuator.

 

have you looked to see if the throttle plate moves at all when you have someone step on the throttle? the engine does not have to be running to see.

 

Does not move stays at the 30% position have tried other throttle bodys aswell.

 

maybe the pcm is no sending the proper power signals. do you have a 5 volt reference signal on one of the position sensor pins? maybe thats why your not getting a reading? missing the ref signal?

 

Yes I have the 5v refrence and the TPS sensor is reading aswell says 30% also the pedal is reading right when i tested it.