I just installed a 5" Autolite tach with shiftlight in my 93 GT. I have all the wires hooked up, but whenever I set my shift point (i.e. 3000) then start the engine and rev to 3k +...my shiftlight never flashes and sometimes the needle will only go up to the shift point and shake, even tho the motor is actually higher than where the light should be. Has anyone installed one of these before and ran into this problem? The ****er is brand new. I have the green wire going to the negative on the coil, black wire to ground, red wire to a power source (when the key is on), and the white wire to a interior lightingpower source. Everything else works normally. When the key is on...I can set the shift point...I turn the lights on the light on the tach comes on and dims when I dim the interior lights, I just dont have a shift light. And YES it is plugged in

 

Are you aware that it has to be set w/ the key on engine off?

 

Yes, I turn the key back...or forward, set the light with the dial...then start it and it doesnt work. I think I know the problem. My power source may not have enough juice.. I got lazy and hooked into the REM wire going from my headunit to my amp. Ima find a stronger source tomorrow and try it

 

exactly what i was thinking.....when it shakes like that, its either not grounded, or you need something a little stronger. Chekc your ground too though, because that happened to me.

 

That was my problem. I simply needed more power. Right now I have it hooked up to the positive terminal of the battery and control the power with a toggle switch under my head unit. Until I can find the right ignition switch wire! Anyone have a pic of the right one?

 

Get a test light and probe around, you'll find it. I'l lsee if I can log in to the wore diagrams from here, but I doubt it.

Ryan

 

THIS tells the pin # you should use and has a link to a pic showing the install.