CD/radio install blows tail & gauge lights fuse.

[Manxman]

10/1999 cab chassis:

have twice installed a new CB & a used radio/CD player-on both occasions the tail light fuse has blown, knocking out the instrument lights as well. It's was 10A mini blade fuse in the engine bay, currently 7.5A and blown..

The original radio cassette had 2 adapter power connections: a switched accessory-on +12 -blue- and permanent feed(?) +12V-yellow. I do not know which is the illumination only for the OEM radio-cassette.

the Earths, all black, are joined together.

the blue wire has the accessory wire-red from the radio and red-for the CB joined to it.

With the key off everything is off, with the key on accessory or run the CB works and the backlight in the radio display lights up-but nothing else of it works.

I have connected yellow to yellow on the radio, hoping that it would provide 12+ permanent to hold the memory, but I suspect that cct is dead ATM-WHY?.

Only 2 speaker ccts are connected colour and mate to colour and mate, & all other wires cut off at both connectors.

There are no shorts in the adapting connectors nor to any metal framework. This is the second radio CD, the first one had a CD loading motor working, but no sound/display. This one-nothing, and wired the same. I think it has a CD in it as I can't feed one in.

Why did the fuses blow? Memory retention doesn't use Amps-EVER!

It appears I have some wires crossed-Tojo deliberately made the connection different from the obvious common "standard", just to make it hard for the unwary. Swines.

I've made an error.

The Black wires-Earth, need to be on car pin 7, not pin 9 [which is the external amp activator, designed for +12V, max 300mA]. I'll shift the wires and report back. The CB is earthing through the chassis, tail and gauge lamps, but the radio has no power for the memory, it having been shorted to the chassis by the incorrect earth wire, which is attached to the radio case internally.

Unit is dead! Cannot turn on. Have replaced fuses, repositioned Earth wires, CB is fine, but this thing is useless.

Edited June 4, 2012 by Manxman