Mph gauge drops to 0mph

[zippityDu]

I recently replaced my SI board with a refurbished unit with new batteries. From what I can tell, each gauge is working properly.

the only issue I am continuing to get is that the speedometer drops anytime I hit 48mph or higher…it drops to 0. Until my speed gets back to under 48mph and then works properly again.

I check the speed sensor at the diff, connection looks great. Cleaned it, and went for a drive and the same issue continued.

before buying a speed sensor replacement, I wanted to confirm that this is the best next step to resolving my issue.

any feedback is welcomed!

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[reelizmpro]

Next time it happens, try smacking the dash above the speedo. If it springs back to life, it's more than likely a bad connection to the speedo. You could try to reflow the solder joints on the speedo itself and PCB before swapping it out.

[zippityDu]

Smacked dash and remains at zero. Is this leading more towards a bad speed sensor? Are these known to fail?

[82eye]

Smacked dash and remains at zero. Is this leading more towards a bad speed sensor? Are these known to fail?

no. you can replace the sensor but it's just a magnet. fail rate is almost zero. problem will most likely be at the cluster or dme. my money is on the cluster.

[zippityDu]

Well, I replaced the SI board with new batteries. What would you anticipate faulting at the cluster?

[82eye]

Well, I replaced the SI board with new batteries. What would you anticipate faulting at the cluster?

the solder joint flows on the pcb boards degrade taking the cluster out. new flows or a new pcb board fixes it. bavrest does that sort of work professionally but if you have the tools or work with electronics it isn't supposed to be too bad to fix.

first thing is to check all the physical connections and make sure they are tight and making contact. then move on from there.