Ok, please see if you can diagnos this very strange gauge/light problem I have or tell me where to start looking.

Here's what happens:

Headlights turned OFF, everything works fine, all guages are cool.

Turn the headlights ON, and it gets all weird. When I pull the headlight switch on, the right 3 gauges go dead: tach, battery, and oil pressure (right? ...anyway, the 3 right most ones). The speedo and others on left side work fine.

Also, along with the gauges going dead, the dash light on the right side (behind the dead gauges) goes out as well as another dash light over by the AC/Heater controls. But the light behind the remaining working gauges is normal.

There's more. When I switch on a turn signal, the 3 dead gauges will flutter in sync with the turn signal (they will kinda jump up a centimeter or so in conjunction with the turn signal blinking)

And lastly. If I rotate the headlight *** (the dash light dimmer) while the lights are on and the gauges therefore dead, the lights will go in and out - flash on/off, on/off , etc. - as I rotate through the range of motion/dimness. And of course the gauges jump alive while this happens everythime the lights go out and then are dead again as soon as I turn the *** a little further and the lights come back on.

Any ideas on what would cause this and how I can fix it, its quite annoying and looks damn ridiculous?

I am not an electronics person and so don't know how I would fix it unless I got my Dad's help who is an electronics whiz. I wouldnt mind taking it to someone and paying them to fix it for me if I knew it would be a modest fee, but I am afraid they either will not be able to figure it out and/or will charge me a large amount of cash due to the time.


Any ideas/help?

Thanks guys.

 

I had a same problem with a friend's 85 Z28. It turned out that one of the pins in the harness that the dash cluster plugs into was bent and not making contact. You should ensure that all of these pins are properly positioned and making good contact. A similar situation can occur from a split or break in the trace that goes through the back of the dash cluster.

 

Thanks Jim.

 

Ok, I finally got the whole gauge mount out and the gauges off.

Someone else said it might be a break in the circuit board behind the gauges too, so I dug all that out.

However, now how the heck do I know whats wrong? I don't really know what I'm doing here.... I got everthing out but I don't know what I am looking for and if I find it, how to fix it.

I looked at the connector pins and everything looked ok to me, nothing looked bent or anything. But I can't be sure I guess....

Any ideas or help would be great, now that I have a car with nothin in the dash...

Thanks.

 

If you look at the back of your gauges, you'll see a clear plastic layer with a bunch of copper lines on it. Those copper lines are what transmit the electricity to the various places. Physically examine those lines for breaks or tears. it's VERY common for the plastic (and subsequently the copper) to tear at high stress points.

Examine the sockets in the dash that the cluster plugs into. make sure all the pins are there and positioned properly.

Get a digital multimeter, and read the instructions that come iwth it. You need to know how to do a continuity test (sometimes called an ohm test) and you need to use that new-found skill to diagnose the wiring both in the gauge cluster and potentially in the car itself.

 

Check over ever lil peice of plastic.. this happend to me.. same problem.. film was cracked just before u plug one of the dash lights in.. use a volt meter and use the setting where it beeps.. go to each spot where the conector is on and trace the brown circut and test it every little bit for power.. if u have a lil crack dont go histarical.. get ur soldering gun out and do that.. i did it and havent had a problem.. but my problem was it was cracked just before a dash light so it would feed power to my turn signal bulb in the dash and light it up and make all the gauages go like that.. if that dont work.. then i dunno what to tell ya.. it just takes time.. i learned that one very well and im only 16 it was so agervateing takeing everything apart and wanting to drive so bad. goodluck