Got a short when putting the Auto in reverse.
Fuse blows and no Revese lights

The volt meter goes from 14v to 11v when the car in at idle.
Any fuse below 25amp blows sky high, anything 30 will hold but warm up enough to burn after 10 second but lREVERSE lights still dont light up

Have disconnected all towbar cables, all cables at boot lid, ie the ones that light up the number plate. Still shows a load on volt meter in dash,
Load is so much that the interior light dims

The circuit from the fuse box ok as i tested with the "close circuit" tester, its lights up but there no change on the dash volt meter.

Obviously from fuse box to bootlid lies the problem. Any ideas?

Car is as seen, ED Falcon Auto 93

check the bulbs and the bulb holders, check to see that wiring hasn't rubbed through.

ok, this might get complicated to explain but i'll do my best to keep it simple. loading up a circuit with bigger fuses will only do a circuit damage. if the wiring in a circuit is only designed to carry 10 amps, it develops a short and u put a 30 amp fuse in there, the circuit will carry 30 amps until it blows.

ok, to diagnose. connect a test light across the blown fuse holder. i use a paperclip or splitpin for the alligator clip side of things. a test light works by providing power one side and an earth(your short) on the other. if u have a dead short the test light will light up. then it's a matter of unplugging components one by one until the light turns off. and it's safe, doesnt do any damage to any circuitry.

i start at the furthest part from the fusebox and it doesnt hurt to start with the easy stuff. start with the lh tailight assembly, then the rh etc until the light turns off.

does that make sense?


a common place for most falcons to come adrift is where the harness comes thru the rh wheelarch at the back seat. it rubs thru on the backseat frame cutting wires shorting to earth.

I've used the testlight b4 so that'll be fine
sounds like i should use the process of elimination to find the short

Will certainly try that tomorrow cheers for the tip

process of elimination is exactly what it is. it could be something as mentioned before that a globe is shorting out internally right up to a dud reverse light switch on the trans. one by one u'll find it