I replaced my transmission on my 99 blazer, boy that is a big job. I got it all back but I have one wire that I can't find where I took it from. It is running off of the big plug that goes into the top of the transmission just behind the filler tube. It is a short wire with a two wire male plug with a blue seal on it. It must either run the vss or help run it, because my speedometer will not work and the transmission will not shift. I have been told that without the speedometer working the transmission will not tell the ecm to make the transmission shift. If anyone can help it would be great.
Also does anyone know of an easy way for one person to remove and replace the transferr case on these blazers. I tried several different jacks and it is made so out of balance it was a real job getting it back in. Maybe some special jack is made to help handle it.
Thanks,
Jack C.

 

There are two on the back and one on the front. Check out the NV236 wiring thread in the tech article section for information on what wire colors go to which sensor. If your speedo isn't working, try swapping the connectors on the two rear sensors and see if that changes things. The pulses might be different between the prop shaft speed sensors for the TCCM & the VSS.

 

check out the pix on this 236 and see if anything matches
4WD TRANSFER CASE CHEVY S10 BLAZER JIMMY ENVOY ZR2 4X4 | eBay

Attached is the wire colors I have on Alldata

 

Hey guys thanks for the heads up on the transfer wiring. I think that picture you told me to look is great. I think that plug over the upper part of the chain area is about where my little wire will reach. Soon as I can get it back in the shop I will try it. If that don't work I will switch the two on the rear of the case. Thanks,
Jack C.