Hey Guys, I have all my gauges working but am having a hard time getting the speedo to work. I have a Howell harness that has the wire for the speedometer already labeled from the ECM just needs hooked up. I also located and removed the VSS Box and hooked the ls1 speedo wire to "c" on the VSS Buffer pigtail but am not getting anything. My car is an original TBI 5 speed car VIN E with no cruise control.

These are the wires on the pigtail plus the yellow and purple VSS wires.
C2
A)Black/White = Ground
C)Tan = Instument Cluster input
E)Red = Cruise Module
F)Brown = ECM input
H)Pink/black = Ignition

C is where i hooked it up but it doesnt work. Do i have to ground the black and white wire or add power to any of the other wires to make it work correctly. also should i discard the VSS box or do i have to leave it hooked up and just tap into the single wire.

I'm lost on this one, i've tried it several differnt ways and still get nothing.

 

I hooked my VSS output wire up to the tan wire and it worked like a charm. Don't have the VSS buffer box hooked up when you do this, take it and toss it out the window. You won't have a cruise control without it though, but with it, you may not have a speedo.

 

Yeah, There may be something else going on then. I tried both brown wires, there isnt a tan one on my VSS box there are actuall two brown wires. But the wiring diagram says the brown wire in "c" goes to the instrument cluster so i hooked it up there. Got nothing. I have some time to play with it today so i'll see if I can figure it out..........jt

 

I am having the same problem, where is the VSS buffer box? Do I just disconnect it or do I need to splice some wires to bypass it?!? Help! Thanks

 

If yours is a Z-28 you wont have the buffer box.

 

There is a yellow buffer box on the passenger side of the dash where the cruise control box is located. Only the TPI cars had the ones like this, the TBI cars had them on the speedo.

 

mine is a 92 rs and i hooked the brown wire up and the speedo works great. it was in pin c also