samsonhusky

i have a 85 gt that the stock tach isn't working, im not sure which wire to run the coil i've looked for gr/yl and gr/br wires no luck, can i just run a wire from the back of the tach to the negative side of the coil

FoxGT

Jump a wire from the tach - to the "sig" spot on the tach. Follow the grid on the back of the gauges to find out what color the wire is. sometimes it's tan with yellow line, somtimes brown with yellow, sometimes brown with tan line. Some get dirty or fade.

The wire for the signal will run from the back of the gauge out through the firewall on the drivers side, into a connector, then to the coil - if i'm not mistaken.

I'm not 100% sure, but I believe it's a 4 wire connector... (or maybe that's the one going to the tfi. Either way, you can trace it from the back of the gauge.


All the rest of the gauges are working correctly right? (this means that the power & ground for the gauges are working properly & the problem is in the signal line. (there are 3 wires required for the tach to work correctly)

samsonhusky

the only gauge working is the speed, i ran a wire from the tach to the negative tried all three screws 2 killed the car, 1 worked but couldn't start the car with it hooked up. the grid is the green plastic stuff right, guess i need to unplug the wires so i can pull it out futher so i can see where it leads to, The wires under the hood is screwed up if i find the wire that leads from the tach could i slice into and run a wire to the coil

samsonhusky

also the tenp gauge could i slice into that wire and run it into temp sending unit

FoxGT

Well there are one of 3 things going on here i'm assuming. If the car still has the stock '85 body/dash/engine harness then i'd say more than likely you have a bad ground wire. If not then you probably have a bad power wire.
Or of the gauge or wiring isn't factory then chances are you'll have to repin the gauges

You don't have to cut the wires out of it. You can take the connector out of the plug by using a small screwdriver. I had to repin an '86 harness to run 87-93 style gauges in a friends car I built

The wires for all of it are probably still there they just are split or in the wrong place. since all of the other gauges aren't working either i'd say that the signal wire isnt the problem. It's more than likely going to be ground or power. I'd lean more toward ground though.

1992gt400hp

make sure that the wires going to the battery side of the solenoid arent broken... i know that at least one of those fires up your wiring harness to the dash... is the tach stuck by chance? mine is haha! at 4500