I bought the 5 inch tach with the shift light on this site, and had it installed at a local car audio place. The shift light works when you push the red button, the display light works when the headlights are on. But, the RPM reading is not working. It is just jumping constantly between 0-1500 rpms, and when gas is applied it eventually goes to 0 and just sits there. Any ideas? I dont know if it matters, but the car is a 2006 mustang gt.

Thanks

 

Ummm did they get a tach driver? I'm pretty sure you can't just route it into the stock rpm and expect it to work....

For instance on the Termi I had to get a tach driver from ford to use my tach.

 

I dont think they used a tach driver, it was just whatever come in the box. I think all that was in there was the tach, the shift light, the mount, and the wires. More info please.

 

You have to get an adapter to run that style tach on distributor less cars. If you do not have this and it sounds like you don't, then you need this part found here.

http://www.jegs.com/p/MSD/752136/10002/-1

 

Is this the tach you have? Autometer.