A couple of months ago I was having vibration issues, I went through and fixed all possible issues with the suspension, u-joints, wiring for the VSS and the trucks been great. Well about 2 weeks ago the vibes came back with the 452 code with no speedo issues. I went through all the wiring again and everything was fine, so I broke down and took it into the dealership, they couldn't find anything and suggested the above, a bad instrument cluster or PSOM. Another problem just started shortly after, the amperage gauge swings far left and comes back to where it started and the only thing affected is the headlamps which dim, but only during the sweep of the gauge. I haven't had time to check it as of yet and it seems to be happening more frequently. While searching for possible solutions I found a thread saying a possible fix is to check that the PSOM has been adjusted for larger tires. I have 33's but I'm not having speedo issues. Any help would be appreciated.

 

My manual states the PSOM receives a signal from the VSS (DSS) converts it to 8000 ppm and sends that info to all components that need vehicle speed info, including Speed Control Amplifier and Power Control Module(PCM). I only have the Electrical and Vacuum trouble shooting manual, not the diagnostic manuals. In the circuit operation section, after descriptions of how the circuit works, there's a referral to diagnostic info in the service manual. So when the dealership said they couldn't diagnose the modules, were they saying they wouldn't because Ford doesn't make these parts anymore and FU, you're on your own?

 

bump

 

The dealer is practically worthless. Too lazy to do any work on something older than 10 years, and not competent enough to work on OBDI. I'd try a junkyard cluster.

 

Do the pcm's go out often or is it generally the PSOM?

 

Most of the time when the PCM goes out it won't go into diagnostic mode.

 

thanks

 

What models will work and from what years? 87 - 96, all years? Does it have to be for a 5.0, E4OD? What's my parameters?

 

You can use '92-'93 5.0 E4OD computers.

 

Is this the job ahead of me to swap the cluster or is something missing?


Actually, that procedure looks to be for 87-91. If you are working on your 93, its quite easy.

Take off the headlight ****

Pop off the horizontal trim pieces with a screwdriver or something similar, then the screws that are behind the trim. If I remember right, you can use either an 8mm socket or a torx bit.

The front of the instrument panel will then pull right off. Give it a good pull, its still held on by clips even though the screws are out.

Unplug the electrical connection for the F/R tank switch right next to the headlight switch. Even if you only have 1 tank, there is still a connection there for the fuel pump.

Take off the screws that hold the gauge cluster in place, then pull the cluster back far enough to unplug the electrical connections from the back, then take out the cluster and change the bulbs.

As Vampyre said, be careful not to damage the shift indicator cable, I am not sure if it is even an issue on the 92-96s because I have a manual tranny. If it is, you can probably just lay the cluster down and change the bulbs without taking the cluster completely out of the dash.

I have had mine out quite a few times, I think I can do it in about 5 minutes now.