99 chevy blazer 4x4 ls

so i've been reading through a lot of threads, and it seems like everyone can find the VSS except for me! i have a new speed sensor and i've been looking all over the transfer case, but i can't seem to find where it's at. all other plugs for the sensor will not fit into this sensor. pleeeeease help meeeee!!!! thank you!

 

um i dont believe the vss is on the transfer case. last time i put one in it was on the passenger side of the tranny i believe it was being held in with 1 bolt.

 

It's on the transfer case output. It's location depends on what transfer case you have. How many buttons do you have on the dash for the 4wd? Also, are you sure you have the correct part? I believe they are different depending on what transfer case you have.

 

it's a 4 button 4wd setup 4 auto, 4 hi, 4 lo, and 2 hi, i got the sensor from napa, and there is no sensor anywhere on the transfer case that looks anything like the one that i have. how can i find out what sensor i need if the one i have isn't it?

 

There will be two sensors on the output housing of the transfer case. You are looking for the sensor with the light green w/ black tracer & purple w/ white tracer wires going into it.

The sensor should be a screw in type sensor with an o-ring seal, not the bolt on type. The part description should state that it is for the RPO code NP8 (NV236) or NP4 (NV136) transfer case, but a lot of parts stores have gone dumb with their descriptions.

If you need to, take the sensor with you so the counter person can match it up appropriately.

 

thank you so much for your help! turns out they sold me the wrong sensor for my transfer case!

 

Hi. I am a new user here, though I have owned three S-series Blazers (a 1985, a 1995 & 1/2 and now a 1999).

The 1999 is an LT with the four-button (2wd, 4hi, 4low, 4auto) transfer case.

On my 1999 S10, I am looking at replacing my VSS as discussed in this thread. When I go to order a new one, the correct one that comes up is, Delco 15547452, described as:

SENSOR,VEH SPD 4 WHEEL DRIVE; w/ELEK SHFT TRFER CASE(NP1)

Now this differs from the postings here, which say NP4 or NP8. If that is the case, it looks like the correct Delco part is 12376520.

I'm not a car guy, so I don't know an NP1 from an NP8. Sorry for a stupid question, I just wanted to double-check before I ordered; two parts places insist that the one I want is the NP1, which is a screw-in, not the bolt-on.


Any advice?

 

NP1 is the NV233, NP8 is the NV236 (w/ Auto4wd), and NP4 is the NV136.

The VSS for the NP8 transfer case is AC Delco PN 213-347. And I think that all of the speed sensors in the NV236/NV136 transfer case (3 total) are the same.

Check out the NV236 Wiring thread found in the Tech Article (DIY) Index link in my signature below to find the wire colors for the front & rear prop speed sensors & the VSS to make sure that you replace the correct one.

 

Blazer is still in the shop getting its control arm replaced, so I've not tried this yet.

I'm ordering the speed sensor for the NP8 tonight, based on your detailed information.

I found the other thread with the drawing and color information. It angers me that I was charged $65 for labor to replace this sensor at a local small shop the last time it went bad, and that was with me bringing in the sensor I bought at the dealer when I could not find where to install it.

 

Got the VSS replaced. It's been working lately, but I replaced it anyway with the NP8 part and it matched/fit; the diagram posted here in another thread was just what I needed. But I don't think the sensor is the problem.

The wiring seems in bad shape; I could not see colors at the connector at all, it seems carbonized; perhaps the aftermarket catalytic converter nearby is getting it too hot and burning it. The split-loom tubing is also damaged.

I want to replace the connector, as I think it may be my actual problem. I think the wires are shorting at times.

When I test drove it, I had no speed for a block or so, then it kicked in and started working again. It had been working for the last 3-4 weeks, and the sensor is not that old (two years or so), so this all makes sense.

I've been trying to figure out what part to order for an NP8 VSS connector; I know GM usually has kits with the plug and like 6" leads.

Any suggestions?

Thanks all for your great help here.