4Hi not working
 

Hi evreyone

I was wondering if anyone could help me with a 4wd problem I have.
It's a 2001 Blazer with 3 button switch, 4x4 stop working a while back,
I managed to reset it once by disconnecting the battery and now, no lights on the switch light up, they do light up once i start it but go out after a second. if I put the truck in neutral I can shift to 4Lo and it ingages but not 4hi, I have since found that the actuator under the battery tray was on constant vacuum so i changed the vacuum switch on the T/case that was jammed, but still no lights and no 4Hi, you can hear the encoder motor shifting when the trucks in neutral but nothing works when in drive , I've tried a Tccm and a switch from a scrap yard and it's the same thing.
My question is; Could it be the encoder motor that's bad even though I'm able to shift to 4Lo, possibly it's not able to sense the 4Hi position and therefore not completing the shift,

Any help is appreciated
Thanks !!

Have you checked the codes? There is a tech article discussing the process for reading the codes on the NV233 transfer case that your truck is equipped with.

Did you check the connector at the TCCM for corrosion?

I have checked the Tccm for corrosion and there was none, but I have not checked for the codes, I believe in order to do that I need to groung pin 13 ? Correct ??

Isn't that what the tech article states? :icon_wink:

Ok got the codes, I'm getting 2 flashes on the switch