Gremlin in my dashboard.

[randyfristoe]

My tach goes dead and my FWD lights glow dimly.

This first started about four years ago. Only when driving at night with my high beams on, after about an hour of driving, my tach would bury itself on the high side and sort of work in reverse. At the exact same time the FWD/low range lights would come on and glow dimly. after turning the high beams off and driving for another 20 min, everything would go back to normal.

Over time, this has become a more recurring problem with it starting to happen during the day, regardless of whether my lights were on or not.

eventually this got to the point that it would happen every time I drove after about 30 min, but would always go back to normal after shutting the engine off for several hours.

the Tach never does respond the exact same way. Most of the time it would bury to the high side, but more and more it would just quit working...always the same with the fwd lights.

Now the most recent occurrence leaves me with no tach and with the fwd lights glowing dimly constantly. It has seemed to have stuck itself in this mode and doesn't go back to normal anymore.

My FWD does work when this is happening. If I push the button to engage it, it lights up to full brightness and engages.

If anybody has any thoughts or ideas, I would love to hear, because I have absolutely no idea where to start looking for the problem.

 

[ragajungle]

randy,
Welcome! My 94 Ex Sport and my 89 Bronco II both do the wacky Tach thingy-still have now idea why. I have heard the the computer causes the Speedo to flake out but no comment as of yet on why the tach would flake. It might be coincidental to the glowing 4x4 button. On a truck that old you might cause more problems poking around the wiring harness.

 

[randyfristoe]

I don't believe that it is coincidental as both occur at the exact same time and there is some sort of a faint click that I hear when it both starts and stops. I'm not sure if the noise comes from the tach or somewhere else behind the instrument panel. Is this something that could be happening because of a circuit board, or is it more likely a wiring harness problem. I suppose it could be a computer bug, but I doubt it.

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the stock 91-94 section.

 

[randyfristoe]

new occurrence. After about a week now of my tach not responding and my fwd/low range lights being dimly on, I got frustrated and started tapping on my instrument panel dead center of the tach. I noticed that my tach would rise up a little and my dimly lit lights would fade, so I proceeded to hit the glass (plastic) with my finger tip pretty hard and on about the third smack my tach started to work and my fwd lights went off.

Does this sound like a tach problem, or is there something else back there that could be the culprit?

What part of the puzzle links the tach to the fwd control lights.?

 

[ragajungle]

a definite short. You could probably pull the cluster and reseat connectors for starters.