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"Key In Ignition" Circuit Powering of Accessories

A big thanks goes out to Neal Barrentine who took the time to writeup the information found herein.
I've never liked the idea of leaving my VW's key in the "ignition on" position just to be able to power my stereo. With the vanagons engine having been swapped out to subaru power, I hear the fuel pump cycling regularly when the key is on but the engine is not started and I worry about this and other drains on the battery resulting in a drained battery after listening to the radio for a bit. I'm positive that a few therapy sessions would solve my worrying problems just fine but I thought that this would be a fun upgrade so I cancelled the therapy appointment and did the mod listed here instead. I found Neal's excellent description of the modification out on the internet and copied it here in the hopes that other folks could it to their own use.

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. 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/Tools needed:
  • 16-14 Gauge Insulated Crimp-On Butt Connector (see pic 01)
  • Crimp Style 1/4" Female Spade Connectors (see pic 02)
  • A Bosch (or other) 4 or 5-pin relay, usually available for $5 or so.
  • 36 inches - 14 Gauge Stranded Wire (preferably red)
  • 36 inches - 14 Gauge Stranded Wire (preferably brown)
  • 24 inches - 14 Gauge Stranded Wire (preferably blue)
  • Wire Cutters
  • Wire Stripper
  • Crimping Tool
  • 2 Zipties (optional)
Optionally, you can use a soldering gun to splice your wires in which case you'd need:
  • Soldering Iron
  • Solder
  • Heat Shrink Wrap
  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 carefully 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 multimeter, find the terminal that the wire connects to on your fusebox. Connect one lead of your test tool to that terminal and the other to a known good ground on the van. Test the wire for continuity when the key is in, but not when out. If test fails, repeat the previous step until you find the proper wire.
  5. Find a nice location, somewhere between the fuse block and your stereo to locate your relay. Use tape or zipties to mount the relay so that it does not add to your van's rattle count.
  6. Find the place on the grey and black wire where it runs closest to your new relay. 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. Using a length of your blue wire, splice into the grey/black wire with a butt connector or by soldering. This allows the circuit to remain stock and also trigger the relay. Connect the other end of the blue wire on the relay that corresponds to terminal 86 on the relay. (see Pic05)
  7. Connect the power wire from your stereo/amplifier/8 track player to the wire on the relay that corresponds to terminal 87 on the relay. (see Pic05)
  8. Run your brown wire from ground to the wire on the relay that corresponds to terminal 85 on the relay. (see Pic05)
  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 corresponding with terminal 30 on the relay. (see Pic05)
    Note: Install an inline fuse between your source of power and the relay. That way if the relay goes bad or you accidentally touch the line to ground, you'll only blow your fuse, not fry the wire or worse. Depending on the amount of power your stereo or accessory requires, you may have to go with a heavier duty relay but 15 amp should be okay. The smaller the amp number, the faster your fuse will blow if the circuit is overloaded.
    Another Note: You could also extend a wire from terminal 30 to your radio to serve as the "always powered" wire to your head unit that powers the clock and pre-set station memory.
You should now be able to power your sound system or other accessories by inserting the key into the ignition switch.



Pic03 - Generic Relay

Pic04 - Removing the fusebox

Click to Zoom
Pic05 - The circuit