Most of the time when I start up my 87 sammy the fuel and temp. gauge go to max and tach doesn't register anything.  However, every now and then all 3 gauges will work.  Its either all or nothing...... none of them work or all 3 of them work.  Any idea what could be causing this.  Could the voltage regulator do it??  Thanks in advance for your help.

Jeff

Check the grounds 

I got the same problem but my tech works good! & I even check the ground?

What is the best way to check this?  Do I need to remove the gauges?  Or, do I just need to remove the panel underneath the steering column?  I did notice a wire there that was hanging coming from a large bundle of wires.  I didnt know what it was supposed to go to so i left it as it was.  I don't have a wiring diagram and I didn't want to short anything out.

Jeff