Hi guys, I've been busy pouring money into my new to me 2007 F250 getting it ready for a 2000 mile road trip starting tomorrow night. I had a high pressure oil problem, so got that fixed (stc screen) and a new oil cooler as well as a coolant flush. I picked it up yesterday. Today I took it to have an aux line installed in the radio so I could use an ipod on the road. While driving home from that appointment, I observed that the speedo wasn't working. A quick visit to the forums told me that I probably had a bad VSS. I stopped at ford and picked up a new sensor $95.00 (ouch). I replaced that and it did not solve the problem. I took the truck back to the shop that did the work, and they tried just about everything to fix the issue. They reflashed the pcm with the newest update, swapped my new vss with one from a running shop truck, checked the connectors on the trans sensors, and all seemed well. We're all at a loss as where to go next. I looked at what the radio installer did, and even went so far as to unplug the power to the ipod adapter, and none of that worked. Would a bad sensor on the transmisson give me a speedo problem, or is that just the one on the diff?

Thanks
Ryan

 

After careful consideration, the only likely suspect was the wiring for the Aux input to the stereo. I disassembled the dash panel and removed all of that crap, and voila! speedo works again...

Ryan

 

Wouldn't a thunk it. Did they tie in somewhere they shouldn't have maybe? Audio connections should have been to the head unit and power also (i think). Maybe something not connected to the install got disturbed while working back there. Too weird.

 

Rusty, that's the confusing part...but several other people seem to have had the same issue...I didn't see anything where he tied in that looked like it would short to ground or cause any interruption...who knows..We leave for Georgia tomorrow night, so I was really on a time crunch!

 

They may grounded the VSS line to the head unit.
It's easy to miss it.


Sean