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Radio Power From Key-in Circuit

Powering the head unit from the "Key in switch" circuiit
From: Neal Barrentine
Model/Type:  1986 and newer
Symptom(s):  Radio drains battery

Powering a sound system from the "key in ignition" circuit on a
1986 and newer Vanagon

There not being an accessories position on the Vanagon ignition
switch, the only alternative to having the sound system wired "on" all
the time was to only listen while driving. This presented a problem at
the drive-in theater where the soundtrack to the movie was broadcast
over the air on an FM frequency, and I didn't want to leave the key on
or the engine running for the two hours the movie was playing. I also
didn't want my stereo hard-wired "on" all the time because I or
someone else would leave it on and drain the battery. Also it's just
plain amateurish. Finding out that the Vanagon did have a "key in
ignition" circuit (to let you know that you have opened the door with
the key in the ignition and you will hear this annoying chime until
you take the key out of the ignition or close the door,) presented the
perfect opportunity to have that circuit trip a relay, thus providing
power to the sound system.

Parts needed: The socket, or holder, that a relay plugs into. There
are some located on the top of your fuse block, but if they are like
mine, they are already spoken for. I got one from a Jetta at a
wrecking yard. Van Cafe calls these things "relay plates" and actually
sells them in their "Headlight relay kit" with the relays (which is
another must-have for your Vanagon.)

Also needed is a Bosch 4-pin relay, which could be gotten the same way
you got your "relay plate." I bought mine from the VW dealer for under
$5. It is the light grey one with the big 53 on it. It's rated at 40
amps, so should be able to handle a sound system.

Butt connectors, 1/4" female spade connectors, wire cutters, wire
stripper, crimping tool.

1. Remove the Vanagon's fuse block from the firewall under the
left-hand corner of the dash by removing the single phillips head
screw attaching it to the metal mounting bracket. Lift the fuse block
up and out and let it drop down. (If you have not previously cleaned
the ground connections at the two round grounding blocks just behind
and to the left of the fuse block, now is the proper time. I used a
small brass wire brush and deoxidizing spray. The product I used is
called DeoxIT D5, which cleans and leaves the connection protected
with a dielectric coating. Pricey, but worth it. Available at your
local electronics supply house.)

2. Unscrew the two retaining screws for the bottom steering column
cover and remove it.

3. Locate the grey and black wire coming from the key switch and
follow it through the harness to the fuse block. Achtung!
There are two grey and black wires coming from the steering column to
the fuse box. Make sure you follow the one that comes from the
ignition switch, not the wiper or the turn signal switch!

4. Using a test light or VOM, test the wire for power/continuity when
the key is in, but not when out.

5. Install the relay plate to the top edge of the fuse block. Align
the tabs and slide it on.

picturex1.JPGjust above my thumb is the relay plate installed without the

6. Find the place on the grey and black wire where it runs closest to
where it will reach the wires from your new relay plate. Pull the wire
away from the harness it is in by gently tugging on it to remove the
slack. When you have sufficient slack, make a loop and cut and strip
the ends. Now you should have two equal length grey and black wires
protruding from the harness. Crimp one end of a butt connector onto
both wires. This allows the circuit to remain stock and also trigger
the relay. Connect the other end to the wire on the relay plate that
corresponds to terminal 86 on the relay.


both ends of grey and black wire crimped together - in foreground

7. Connect the power wire from your stereo/amplifier/8 track player to
the wire on the relay plate that corresponds to terminal 87 on the

8. Run a wire from ground to the wire on the relay plate that
corresponds to terminal 85 on the relay.

9. Locate on the back of the fuse block the two red 12 gauge wires
that are plugged to the two large male spade terminals on the fuse
block. These will be on the lower left-hand corner of the fuse block.
Just up from these two terminals are 4-5 unused smaller male spade
terminals. Find one with 12 volts without the key on, and connect a
wire from it to the wire on the relay plate corresponding with
terminal 30 on the relay. (Note: on the relay plate I have there are
two wires crimped together in this position. One of them could be used
to power the "always powered" wire to your head unit that powers the
clock and pre-set station memory.)


blue wire powers relay
10. You should now be able to power your sound system by inserting the
key into the ignition switch.

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