My stock tach and phantom meter both went out. The weird thing is my stock tach would peg out at max rpm when the ignition switch was turned on and then go back to normal idle speed rpm after a few seconds.My engine did not rev only the tach needle moved. It would do this everytime I started my car up. My Autometer tach did not do this and they were both hooked up. The autometer signal is tapped into the blue wire under the hood. They both use two different signals and grounds. The Autometer uses a frame ground under the dash. When I hook up my Kpro to my laptop I get a tach reading signal that shows the Rpm in datalogging.

How can I fix it, I never had this problem on an OBDII? I wonder if I have an electrical problem, my radio fuse blew recently and I have not had a problem with the new fuse blowing. My A/C went out, the switch is working but the compressor clutch is not engaging and the wire going to the compressor is not putting out any voltage. My alamr was glitching so I took it out of the car incase that was causing the problem, it was not the alarm. I took the alarm out mainly because it was so cheap and generic.

 

Wow with all the other symptoms of wiring issues you describe you have to have an issue somewhere electrically. Which unfortunately is a real pain in the ***. I'm heading to work and then to a wedding so I won't have time today and most tomorrow to look it up but you should try to find out what the signal should be for that gauge and test it. Also for the OEM tach.