I have a 1981 'Vette and as soon as I turn the ignition on, the signal light fuse blows. The signal light switch is in the middle so shouldn't draw current. Hazard light work, so I assume that this discounts any issue in the wiring at the lights end. I disconnected the backup light switch, so that should discount any problems there.
I've removed the seats and the side panels on the console. The wires and connectors in there all look to be in excellent shape.
The signal light switch on the column feels soft. Has anyone heard of this switch shorting out?? Any idea how I could check it without pulling the steering column?
Any other ideas?? I've reached the end of my rope!

OK Disconnected the battery and put an ohm meter on the circuit. With the key on it shorted; key off was OK. Reconnected the battery and disconnected the "letter" connector to the CCM. It has a wire running directly to it from the signal light fuse via the backup lights. That seems to stop the immediate short. I've run out of 20A fuses, so will pick up more tomorrow. Not sure if leaving this connector to the CCM off will have any other impact. I tried starting the car and it runs OK. Damn CCM is a PITA!!

Problem Solved. There's a wire running from the backup light switch back to the CCM. Looks like it was shorting out when I started the car. Cut the wire and all is well.

 

Get more rope?
Sorry.. I had to.
It does sounds like you have a short somewhere. I am not sure what all is on that fuse, but if there is a short on the way to something you are still going to blow the fuse even if you disconnect the light or a switch.
I am wondering if you can disconnect the battery and check for continuity between what is normally hot at the switch or light and a good ground ?

 

They sell circut breakers.

or

You could wire it direct and you and a friend watch for smoke.
Then replace the whole wire.

Crude but fast and effective, I've done it as a last resort.

Ralph