NP243 and Transfer Case Control Module wiring diagram

[Awest623]

What's up!

I converted my automatic 98 K1500 to manual a while back. Everything works fantastic except I can't shift my transfer case into 4lo. It will blink the light for a while but won't shift. I assume it's looking for a park/neutral signal that isn't there anymore.

Anybody got some wiring diagrams to help me out?

Specs:
1998 k1500 5.7
4l60e swapped to NV4500
NP243 push button transfer case

Thanks!

 

[Awest623]

Welp, figured it out.

Wiring diagram is below for anyone interested.

The solution is to cut the yellow wire going to pin 16 of the TCCM and short it to the green wire on pin 2.

 

[Awest623]

Test drive complete. 4lo works as advertised. Hopefully these posts can help someone in the future that's dealing with the same issue.

 

[DonYukon]

Just now seeing this I had this issue when I swapped as well I could have helped you sooner. sorry but great job.

 

[Awest623]

Just now seeing this I had this issue when I swapped as well I could have helped you sooner. sorry but great job.

No worries. Tbh I've been putting off fixing it for a hot minute and couldn't figure out which module was the TCCM. I'm still a little curious why it didn't work before. When I did the manual swap I went through the transmission wiring and soldered the park/neutral switch wires. Looking at the wiring diagram I'd think that woulda made it work. Guess I missed something or the TCCM pulled the neutral signal from a different switch?

 

[Awest623]

Maybe the TCCM pulls the signal from one of the column switches? I haven't looked into those ones much

 

[DonYukon]

No worries. Tbh I've been putting off fixing it for a hot minute and couldn't figure out which module was the TCCM. I'm still a little curious why it didn't work before. When I did the manual swap I went through the transmission wiring and soldered the park/neutral switch wires. Looking at the wiring diagram I'd think that woulda made it work. Guess I missed something or the TCCM pulled the neutral signal from a different switch?

its been a hot minute since I did mine but on my 98 with autotrac (if memory serves me right) The transfer case obviously is manually shifted into 4Lo but the transmission doesn't know what to do with the shift points because of the gearing so its erratic with its shifts or doesnt shift at all. Cant remember the pins but basically it modifies the shift points. I have mine on a switch so in 4hi I just lock the hubs and switch the Tcase and I have 4 hi . 4Lo i hit a switch which substitute's a electronic switch in the TCCM and Tricks the ECM to thinking a TCCM is still communicating with it. the benifit Is I have a 2Lo option if I keep the truck in 2wd