Radio wiring question...

[drew at scirocco.cs.uoguelph.ca (Drew MacPherson)]

I think this is in a FAQ somewhere...

Wire the unswitched power (battery) lead on your radio to constant 12V.  
This is usually the heavier guage of the two wires, and has a 10 or 15 amp 
in line fuse, depending on the power of the head unit.

Wire the switched power lead (usually 5 amp or less fuse, lighter guage 
wire) to the key-in-ignition circuit from the ignition switch.  This is as 
close to an accessory circuit that A1 and A2 VW's get to, and is siwtched 
12V+ when there is a key in the ignition.  It's used to inform the seat 
belt warning system that there's a key in the ignition.  The wire you're 
looking for is brown with a red stripe, and is on terminal Su of the 
ignition switch (IIRC.)

You can tee directly into this wire and use it as switched power for most 
modern head units.  If you're powering a radio driectly (ie an old radio 
with no battery circuit) then you'll want to use the Su circuit to switch 
a relay that can power your head unit.

I've done this on every VW I've driven, with teh exception of the 92, 97
and the 99, which all came from factory with this circuit in the wiring
harness for the radio, and have had no ill effects.  It allows the radio 
to be on whenever the key (or any key that fits, actually) is inserted in 
the igniton, and turns it off when the key is removed.

You can access the ignition harness by pulling the lower steering column 
cover off.

HTH,

Drew

On Wed, 23 Jul 2003, Greg Nichols wrote:

> Heres my question.... If you have a radio that doesnt have a detachable face, is there a way to wire the radio to turn off completely when the car is off? I believe the answer is yes because I have it wired like this now- Car off = radio off. This would be ok, but I lose all radio settings, sound settings, cd location because essentially Im just "unplugging the radio". If I hook the radio up to the constant power from the battery and then my switched power source is from the fuse box, I can press off on my radio but the clock stays on. My question to you is... how much will this drain my battery? I cant remember but do dash clocks turn off with the ignition? If they do, how are they turning off but remembering settings? And can I run my radio like that HELP!!!!!
> 
> Captnbr@aol.com wrote:Just connect both wires to the power wire in the rocco. Then you'll be good 
> to go. And you'll be able to turn the stereo on without the key. I love this 
> feature. I wish my Jetta had this feature.
> 
> Brian 86 16v
> 98 Jetta GLX Vr6
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