This bus is #2 of a set of twins we recently acquired. Bus #1 had no Speedo/odometer. Testing through the 9 pin with Jpro showed it was getting a speed signal in the trans and brake controller. Bus #2 had a Speedo that would work after a few miles, but it also showed speed when looking at it with Jpro.

After alot of head scratching, we swapped GEMs. Now Bus #1 had a working speedo and Bus #2 did not. Great. I ordered up a GEM and took it down to the dealer to have it programmed. They could not hook up to the truck with their IDS. I wasn't really surprised because I have never been able to hook up to the computer through the 16 pin DLC either but I was assuming it was because there was a problem with the JPro hardware/software.

And this is where I am stuck. The wiring diagram shows the wire from Pin 7 on the DLC joins the wire from pin J on the EDC and they both go to the GEM. That seems to be the only connection that the DLC makes.

I guess my questions are:

1, How do I figure out why Ford can't connect to the GEM and,

2, What data would I actually get if I was connected? WHen troubleshooting with Jpro about this connection, I talked to one of their computer people and they told me that the only thing that I would be able to connect to is the transmission and since I can do that through the EDC, do I have a need for this extra connector we were sold?

At this time, I have no wiper functions and no drivers window auto down, but I have passenger up and down.

Tim Ball
Manager/Technician
TAC Transportation
Bend, Oregon, USA