Tachometer reads high after fuse holder repair

'86 MJ, 2.5....The tachometer reads high....at idle, indicates about 2500 rpm.
It (and all the other gauges) quit working....problem was that the clutch MC had drooled fluid on the fuse block and caused corrosion....the fuse holder was failed.....i routed around the offending fuse holder with an inline holder.

Now the tach reads high and come to think of it, the water temp gauge reads low...I have checked grounds, checked to make sure I am getting 12 volts to the cluster, made sure the contact strips on the cluster are clean and properly connected,etc..there doesn't seem to be a gauge cluster voltage regulator or anything....I even disconnected the alternator to eliminate the possibility that the output was too high, possibly overdriving the tach...

I had changed the dash assembly, but reused the existing cluster and it had worked properly until the problem with the fuse block came up...

Any help will be appreciated...

OK...is everybody stumped????

Ok an update in case some unfortunate soul runs into this....the tach failed...and by some sort of electrical voodoo was back feeding to the other guages....if i pulled the tach out, the other guages quit doing ther little jiggle dance....i disconnected the tach wiring from the cluster plug....pulled the needle off the old tach...painted it flat black, stuck it back in the cluster...and column mounted a nice shiny AutoMeter tach.:greensmok

Thanks for posting the results of your findings.
It was really informative, now if I can just remember it when it happens to me or Others.
Thanks!

It's kinda funny that the tach took a dump at the same time the fuse block repair was happaning......these thing can drive a guy crazy.

X2, this will be nice when some one dos a search and there is a answer at the end of the thread.:thumbup:


Mine doesn't have a tach but i have a dash from my spare jeep(same year(89) and can't decide weather to try to make it work or just go you route and buy me a dash mounted teach.

Flash.