1989 Bronco II 4x4 5 speed:

OK, I finally got the nerve to take out my instrument cluster to clean up or possibly replace the voltage regulator to fix the stupid gauges, but there's not one! There are two holes for the harness plugs, a speedo cable and some light bulbs.... that's it. There's nothing that looks like a metal box that snaps in to the back, but there is another small circuit board with 2 resistors that sticks into a slot on the far right side. Could that be it? I'd really like to get this back together and working so the gauges are not erratic or pegging high, oil pressure "dances" to the beat on the radio, etc.

Anyone got any ideas?? Thanks, RC

 

Heres what the EVTM for my 87 sez about "All gauges erratic, high or low. Check engine to body ground
& check the ground connection under the dash."

Everything else it mentions covers IVR problems. Not sure, but i dont think your 89 had the IVR.

Best bet for fixing this -or any other elecrical problems-is to get the EVTM for an 89.

 

Thanks for the help 87XLT. It does seem like a bad ground somewhere. Does anyone know where to look for the main engine to body ground wire/strap? I found one from the firewall to the intake manifold but nothing under the dash yet. I'll look at the diagrams in the Haynes book and see if I can figure 'em out, but any help from you BII guys would be appreciated! Thanks again.

 

On my 88 is about the same. Firewall to intake ground strap. On the negative wire from the battery it goes from the battery to frame and then to block.

 

instrument cluster regulator is not one piece. each instrument guage has one a piece.
if you look behind the guage panel you will find your regulator don't look behind your instrument cluster you won't find jack. you need to remove everything!!!!

 

CHEAP 'n EASY FIX!

Negative cable from battery to block was not attached to frame 1/2way down. The bolt on the tab was making some but not enough contact. Fixed that and NO MORE freaked-out gauges Thanks FTE!

 

And thanks for the update, glad to hear it's fixed.