VSS wire for aftermarket navigation

Thanks for the reply. I studied the wiring diagrams from my service manual, but cannot determine if the white/orange wire at the back of the instrument cluster is the same as the one coming from the PCM. Can you tell? It would be a lot easier to make the connection behind the dash than running out to the firewall.

i would assume so, splice onto it and take it for a drive.

OK, I'll give it a try. This is an elusive question. I have been all over the internet and through my service manual trying to get a definite answer with no luck. I was following a lead to make the connection to a wire in the cruise control bundle and wound up blowing a fuse that took me a couple of hours to track down so I am a little cautious.

What sort of electrical signal is this wire supposed to generate? I'm curious for other reasons.

superman279 said:

What sort of electrical signal is this wire supposed to generate? I'm curious for other reasons.

Click to expand...

What I have read is that the Power Control Module converts the ac current from the vss sending unit(s) to a square dc pulse signal. I don't know much about electronics but apparently this is the signal that is interpreted by a microprocessor in the gauge cluster to give a reading of your traveling speed as shown on your speedometer. If someone has a more accurate explanation, please jump in.

I have found a purple wire in the harness coming from the steering wheel controls that emits a pulse, but it is not the right one for my nav unit.

The answer for my 2003 pickup with 5.9 liter Cummins diesel, 4wd vehicle speed sensor ( vss ) wire for connection to my aftermarket navigation stereo: Connect to the white/orange wire coming from the Powertrain Control Module (PCM) that is located in the engine compartment on the firewall on the passenger side. The PCM is the aluminum control box that has 3 small bundles of wires connected to the face. I actually made my connection on the driver's side where the bundle leaves the plastic loom that run high on the firewall. The wire bundle is exposed for a few inches before it enters a black rectangle connection box high on the firewall. Note: I attempted to make my connection behind the dash to save going through the firewall, but none of the wires that I tried including the white/orange wire behind the instrument cluster produced the correct vss pulse.

http://www.jegs.com/InstallationInstructions/100/151/151-1057650.pdf


This should help :thumbsup: