Ok here is my problem, on the dash of my 1998 Sunfire the Temp gauge and tach are erratic at the same time, also most warning lights come on and off at will, The headlight indictaor will flash,

Faulty instrument cluster. You will need to replace it to fix this problem GM has had many problems with these cluster along with some others.

circuitry behind the gauge panel. you will have to pull the dash to see behind there and track the problem down

Computer, replace it.

Have you checked the gauges fuse ?

Symptoms point to the cluster microprocessor. How was it proven? See diagram below.

You have some wiring problems shorting out that is coming from the dash board so if you or anyone you know how to use a multimeter to check the wireing harnesses plus check any connectors that might be just very touching the connector of dashboard which means a bad connection to dashboard.

Hi, airbag deployment rarely causing damage to the wiring in the dash. The gauge cluster may of been damaged internally, but this usually shows up right away after repairs are done. I would check the connector on the PCM it is a cam lock design and if its been damaged or not closed properly it can cause crazy things to happen to the gauges. Good luck.

The click clich sounds like a relay

temperature sender unit top of engine cylinder head make sure its okay
and make sure wire going to it is not grounding
if it grounds or earths it will send the gauge up and down

I have the same problem.. i installed a toggle switch for the fuse so at least I can reset it while driving.. its still a pain so Im thinking my next step will be to drill a hole through the plastic and put in a small metal post to stop the tach from going past 7

has anyone taken theirs into a shop?