Radio Wiring

[39buss]

Happy New Year to all.

Is it possible to power up the audio unit 'on the bench'. My regular auto tech thinks there may be a 'can-bus' (didn't know what that was)in the wiring loom circuit to pulse power. I cant try it in the car as it has a Kenwood 5220BT fitted and the original loom has been altered and soldered to suit the Kenwood and I think the GS amp by-passed as there's a Mutant amp in the boot and the sub works. The idea is that if and when I come to sell the car the original head unit can go back or may be not as the CD changer was missing when I bought it. The Kenwood plays single cd's,dvd's,iPod and USB memory stick so cd changer wasn't an issue.

[Geoffers]

There is a bus system on it yes, although it may not stop it powering up so in theory you could test it loads CD's. I've not tried one outside of a Lexus so there is a possibility it won't power up if it doesn't see the amp.

The bus system is used for the amp. The system volume and tone controls are transmitted through it but may also perform a handshake with the amp on powerup.

The output is at line level but may work if its not connected.

Blue/yellow stripe - Perm live

Grey - switched live

white/black - earth

If you want to try its audio outputs, line level should be enough to power headphones. Its a balanced system so there's no reference to earth meaning you'll have to try each channel independently.

Within the shielded cable:

White: Right+

Green: Right -

Black: Left +

Red: Left -

e.g. You'll need to put the R+ on one of the headphone pins and the R- on the headphone earth. You can't test the left at the same time using one pair of headphones as it will short. You'll need a second pair. You can't use a speaker or the larger speaker style headphone as the line out isn't powerful enough.

The radio does take quite a bit of current so make sure you have a decent power supply.

[39buss]

Thanks for the great answer Geoffers. Its a bit beyond me but the auto leccy will know,and it answers my query. The CD player wasn't in the car when I bought it. When I bought the head unit I asked the seller to leave the plugs and tails to make a refit easier!! if possible.