Aftermarked Tach Short Out

[Ryan Roden]

My 85 fox has an aftermarket sports comp tachometer, it is wired to the fuse box, it works fine when I'm driving during the day, but when I turn my headlights on it shorts out and does not work, and suggestions on what it could be? Thanks.

 

[mikestang63]

check the wires for the bulb to the tach. My guess is you are sharing the ground for the tach and the bulb and the + wire for the bulb is touching ground. You do have an inline/ add a fuse for the tach right? Also the ground wire should be to the chassis or block.

 

[Ryan Roden]

Thank you for the suggestion I will try that