Tach issues...
 

Maybe someone can help me out here i am not to good when it comes to electrical. When i engage my trans brake with the car running or not the tach jumps up like 1000 rpm's. Everything else in the car works fine just when i engage the transbrake. Is this an issue with the tach the transbrake or the wiring. Any help would be appreciated, thanks alot, Nate

sounds like there is an issue with the way the transbrake is wired and is effecting the tach. signal. What kind of ign. and tach?

I have a 6al box with autometer tach.