tach all bars stuck on

[stevkos79]

my 85 gn has all the tach led lit when running
i swapped tach and boost gauge with another and its the same'

do i have 2 bad gauges?

shorted wire?

does anyone have a wiring info on that circuit
thanks ,,,,

[1BADNAT]

I have the same problem with my 87 if you find the problem can you let me no. THANKS BRUCE

[Keller]

There is a tach wire in the underhood harness. Driver's side, not far from the #1 cylinder. Green female connector. Should be left open - not connected to anything.

Anything plugged into it? Like...the fuel pump test connector? That is a common error that messes things up.

[kenmosher]

If that's not it, then contact John Spina at Casper's.

Oftentimes its a broken/bad trace on the back of the instrument cluster and/or a bad chip on the cluster. John's been fixing the clusters for years and can usually pinpoint and fix them pretty inexpensively.

[ajt86]

mine does this too- could it because i have an autometer tach hooked up to my tach wire? thanks

[Keller]

It could. Most if not all tach's aren't set up to work correctly with these car's ignitions. VDO used to mod their tach's for free if you'd send them back. Not sure they do anymore. Not sure of the situation with Autometer.

The signal is a 5 volt squarewave.