Just bought this truck and speedo doesn't work. Previous owner says VSS is new but speedometer doesnt work. I removed cluster and checked with multimeter and theres connection/link from plug to the speedo and ground.
I checked resistance between black and red wires on the speedo itself and there's no link. Blown speedo?
I just want to make sure Im checking it right.

 

Lets start with with what year, trans, 2wd / 4x4, ETC this rig is before we all try to diagnose it...

 

92 W250 4x4, auto, 35" tires, 6" lift, regular cab/short bed, factory silver with black interior.

 

Is this the same truck, that you're brother bought, with the steering problem?

 

yes, its same 1st gen truck. Trying to work out all these bugs out before it becomes his daily work truck.

 

Since VSS is new I'd crawl under the truck and make sure it is still there and plugged in. If it uses a reduction gearbox make sure it is not broken and working properly too.

 

First question I'd ask is does the odometer work. If it does, then the gears in the speedo head are worn out. If it doesn't, the VSS and/or ratio adapter are suspect. Ratio adapter failure is common as they never get serviced. They are available through a number of sources, but there is no one-size-fits-all. Most NP205's have the same drive and driven gears sets in them, but not all. Add tire size and axle ratio each truck will be different. If your lucky, the number will still be on the ratio adapter.

 

In the picture, the set on the left is for the NP205 transfer case. VSS on top, ratio adapter in the middle, and transfer case driven gear on the bottom. On the right is the 2wd set up that goes directly into the transmission tail housing. The driven gear housing on top and the driven gear on the bottom. The fork holds the housing in.

 

Good post right there, Cougar

 

Is there way to check speedometer itself if its working, maybe its burnt out, etc? Thanks

 

Previous owner claims he replaced VSS with a new one