66 Mustang blowing accessory fuse as soon as ignition is turned on.

[Danford1]

I have a 66 Mustang that blows the accessory fuse ( 14 amp, fuse number 1) as soon as I turn on the ignition.

The wiring diagrams I found say the accessory fuse controls Back up lights, Radio, PRNDL light and turn signals. The car doesn't have back up lights, the radio is missing BUT my turn signals work fine.

PRNDL light bulb is good however connector is unplugged and I can't see where it would go.

The wiring diagram shows circuit 140 going to a Yellow 3 way plug coming out of fuse box. I unplugged what was plugged into the Yellow connector but the fuse still blows. I can see another wire on the back of the fusebox going to the accessory fuse but can't find that wire on the wiring diagram.

I want to unhook whatever is on that wire but it goes into a taped harness. Where does the wire go? Remeber, I don't have a radio, no back up lights and my turn signals work...

Please help.

Dan

[coupe3w]

Your ignition switch may be faulty. I would start there.

Try getting help on one of the Mustang forums like Vintage Mustangs.

Edited May 17, 2023 by coupe3w

[Danford1]

Thank you. I’m going to check all wires at the switch. The switch was already replaced but that doesn’t mean it was good. I had brand new parts that were bad right out of the box. 
 

[akirby]

Disconnect everything on that circuit.  If it still blows it’s the switch or wiring.  If not reconnect one by one until it blows.

[Danford1]

That is sorta funny. I can’t find a wiring diagram to show what is on the circuit. If I did I would disconnect things.
 I have two wires coming from that fuse on the fuse box. A black - red which I unhooked and a white wire. No wiring diagram I found has a white wire on the fuse box. Wiring diagrams DO show a fuse with Nothing hooked to it which doesn’t make sense but that is reality. 
 I’m going to have to cut the tape on the harness and see where the mystery white wire goes as something on the circuit is shorted to ground.