flashover15

1967 mustang convertible. 289. I was driving yesterday and lost all electrical power. Checked battery, 12 volts, no headlights, no interior lights all gone. randomly wiggled some wires under dash and power came back. as soon as you turn the key on it all goes away again. More wire wiggling, can not get power back to inside of car. Checked ground from battery to block, good. Any one got any good ideas of where to look next? Trying to find good electrical wiring diagram.

Mustangdemon67

Take a look at the fuse box wiring, maybe something is loose or damaged there. Also check the main harness plug that goes from the outside of the firewall to the inside of the car.

flashover15

Thanks... i will start at the fuse box and work through it.

fastbackford351

Yep. Grab your 12v test light and begin the chasing of the spark.

jlg2002

Go to the starter solenoid and make sure the small blk-yellow wire is connected tightly. From there go to the firewall disconnect and unplug it look for any problems and then plug it back in. Once inside the car the wire color turns to yellow and gos direct to the ign switch. there is no master fuse. here's a copy of a 66 and 68 wiring diagram it should be similar to one of them.