Hello. My truck is a 94 F250 4x4 with a 460 and E4OD. I have come across an issue with my truck's speedometer and odometer intermittently not working, and when the speedo/odo aren't working the truck will not shift. The first time, they only quit working for about 10 seconds and it fixed itself while driving. The second time it happened, I had to park the truck and I tapped on the gauge cluster a few times with my hand and the odo came back and and the speedo worked and the truck shifted. Not sure if that was just a coincidence, but it seemed to start working again as soon I I tapped the cluster.

I understand it could be a few different things such as the VSS, VSS wiring, or something behind the dash such as the PSOM. Since the speedo and odo stop working at the exact same time, and the truck won't shift, does this point to the PSOM more rather than the VSS? So far I've pulled the interior fuses and checked them, and looked at the wiring under the dash and some of the VSS wiring. I pulled the codes and the only codes I got are 553, 212 and 332.

Any inputs/suggestions are much appreciated, thanks.

 

By ODO stops working, do you mean it just disappears? If so, the PSOM likely has broken/failing solder joints somewhere.

You can either try fixing the joints, or replacing the speedometer module.

 

Check the vss located in top of rear axle. That and the electrical lines to it.

 

Yes, everything happens at once. The speedo stays at 0, the odometer mileage totally dissapears, and the truck won't shift. I've already inspected the wires coming from the VSS. Like you said Lead Head, I'm thinking the PSOM might need resoldered.

 

Simple procedure to inspect the PSOM for bad solder joints. Most likely your culprit.

 

So I should just put a new dot of solder on all of the solder joints? any special precautions I should take before doing this?

 

Inspect then go from there. Nothing really special about a PSOM, but no sense tempting fate either.

 

That's the PSOM, not the VSS.

 

https://www.ford-trucks.com/forums/1...s-but-why.html

 

Looks like I'll be repairing the PSOM. Thanks for all of your help guys. I'll let you know what happens when I get around to fixing it.

 

Installed a PSOM from the junkyard today. The issue appears to be gone, however I won't hold my breath until I drive it more. Hopefully it doesn't come back.