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My speedometer/odometer went dead last night after passing over a rough bit of road and then came back a mile or so later during a hard manual shift. No other systems went down, so I presume it is something specific to the PSOM. Looking around it is most likely a problem with the 296 Hot in Run circuit or something on the PSOM board itself...
Is there anything else I should be looking at, common failures?
Check the speed sensor in the rear axle. If it goes so does your speedo. Its only 1 bolt to replace but they have an O-ring so you might want a flathead screw driver to pop it out.
Your vss is fine. You have a power/ground issue. Check your fuses. Sometimes, just removing them and plugging them back in is enough to make good contact and keep ya going.
I have driven the truck over the bumpiest roads I could find nearby in an effort to re-create the problem without success. I also had no success wiggling wires that I could get to under the dash. I have not yet, but will pull and inspect both fuses.
Mine died a couple of years ago. I had to send it out to be rebuilt. If I remember correctly, it's like the PCM in that there's a capacitor or something that corrodes and pukes all over the board.
I have a '92 F150 Flairside 5.8 4X4, that had the same issue, took it to the dealer & hundreds of dollars later told me it needed a new instrument cluster that was special order, took it to a shop suggested by the transmission shop that rebuilt the transmission, 1 hour of shop time traced it the speed sensor, problem solved.
I have a '92 F150 Flairside 5.8 4X4, that had the same issue, took it to the dealer & hundreds of dollars later told me it needed a new instrument cluster that was special order, took it to a shop suggested by the transmission shop that rebuilt the transmission, 1 hour of shop time traced it the speed sensor, problem solved.
Speed sensor won't cause the odo to blank-out. That's a power issue.