speedo only works when wet

Tonka350 · Sep 20, 2012

hey guys so I've noticed as of recently that my speedometer only works after
A: I wash the truck
B: it rains

what would cause this? I've replaced the VSS, GEM and looked everywhere and can't figure this stupid problem out....I've also looked everywhere but the Speedo only seems to work after the rearend gets wet??? any ideas?

my idea is that a wire got pinched somewhere near the rear end and the water is helping to "complete the circuit" ( probably totally wrong ) but that's my idea...anyone ever seen this before? truck is in my sig 2000 f350, 7.3 200k miles.

Chad

7.3powerstroke00 · Sep 20, 2012

The age of your truck I would def lean towards a broke wire that when wet makes contact.... Be a pain to find but very likely the problem....

Tonka350 · Sep 20, 2012

I've sort of isolated the problem because I don't wet the WHOLE underside of the truck when I wash it, I only wash the rear differenatial and such because it's so easily accessible. think this might be the area where it would/could be coming from?

Chad

Arisley · Sep 21, 2012

Sounds like VSS wiring. Or, it could be the hole is dirty where the VSS mounts.

Tonka350 · Sep 21, 2012

really? it could actually effect like that? I'll try that, I'm thinking more along the lines of the wiring...I'm trying to get a whole pigtail from the fuel tank back.

Chad

HOOV3R · Sep 21, 2012

I got a pigtail for mine a while back, it went all the way from the sensor to where it tees into the harness. My wires were broken right where the wires 90 out of the plug.