cluster problem: speedometer, tachometer odometer are sporadic

Its a 92/4.0/aw4/231. Sometimes I turn it on and get only tach or only speed. Sometimes it will start working during drive. if speedometer is not working odometer is out too. All other gauges work normally. Help please...

Wait, so the tach also dies, or works fine? If it's just the speedo/odo it could be the VSS, the wiring from the VSS to the ECU, the wiring to the cluster, or the cluster itself. If the tach also does it, it is probably the wiring to the cluster, try removing it, cleaning all the terminals, and reinstalling.

You may get a CEL stating No Comunication with Bus.

You can also bend the pins slightly to get better connection with the female end. If cleaning doesn't fix it jeep has an updated harness that you have to solder. Its a PITA. There was a TSB on this. You didn't happen to add an overhead console?

that all applies to the 97 and later XJs, but is not relevant on a 96 or earlier with the hard wired instrument panels.

Yes the tach also dies sometimes both speedo and tach.

Sounds like the connector to me. Same exact thing happens to me, I haven't felt like bothering to fix it yet, I just smack the top of the dash till it works again.

For years, the tach and speedo on my '93 XJ 4.0L worked sporadically.

While driving, the tach & speedo needles would flicker and die - and then flicker and die again. Friends would joke about how the car behaved as though we were flying near to
the Bermuda Triangle.

I checked and cleaned every ground that I could find and get my hands on. No change.

I cleaned the main wire connector at the gauge pack. Nothing.

I changed the speedo sensor at the tranny. Nope.

I disassembled and cleaned and re-crimped every pin connector on the wire harness
connector block at the gauge pack. No, not there, either.

I swapped the gauge packs entirely. Twice. Damn. No improvement.

I simply threw in the towel and, for years, accepted the flickering instruments.

Last month, I was inspecting and wiping and detail cleaning the engine - and I noticed
some dirt and oil had accumulated on the oil pressure sensor (near the oil filter).
I disconnected the wires there and gave the pins and sockets a thorough cleaning
and put it back together.

Not expecting anything more than having a clean engine, I drove off to run an errand.
While glancing at the instruments, I saw that the speedo and tach needles were now
behaving (mostly) steady and true.

The needles still glitch every now & then (for only a split second) but, man, what a difference!

I never would have guessed that cleaning the oil pressure sensor connector would
fix my tach & speedo. Go figure.

My next project is to add an additional pigtail to the instrument black ground wire that
is under the dash (near the driver's leg well illumination light) in order to bolster the
ground connection there.

I'll try cleaning the oil pressure sensor. Also the ground under the dash and report back.