With Wings As Eagles: Craig P. Steffen's Blog

energizer's bypassed like a Christmas tree

2008 February 13 08:04

The volkswagen beetle, like any other car, has switches on the doors that turn on the interior light when the doors are opened. In the later years, the original beetle also had a buzzer that sounded when the driver's door was opened with the key still in the ignition. The wiring for this was a double switch in the door pillar that activated two different circuits, one to drive the light and the other the buzzer.

I've seen instructions how to dis-able the buzzer by pullout out the door switch, disconnecting the wires that control the buzzer, taping them up up and then pushing those wires into the door pillar. I don't remember where I read that, and I'm glad I don't. I don't know what kind of lame-brain would dis-able something in a car's wiring by disconnecting wires and then leaving them floating around inside the body, even if they're taped up. First of all, electrical tape comes off over time, and then you have a wire that randomly grounds and sets off the buzzer. Secondly, if you don't like the buzzer, why don't you, say, UNPLUG THE BUZZER itself? It's one of the three relays that are plugged into the relay rack right about the fuse box. Then you can always restore it to original operating condition by putting the relay back in. (And I'm not talking about vintage car issues; someone someday might own your car, and they might want to have it in original working condition.)

Ok, enough bitching. At some point, something must have been wrong with the double switch in my beetle (I don't remember now). I know that the buzzer wasn't working, so I think I pulled out the switch and was going to restore the wiring. Well, the switch was broken. I bought a couple of used switches at a VW show last year, and last night I went to install them. I started by fishing the relevant four wires back out of the hole in the door, which was no picnic:

I discovered that none of the switches that I had worked. I couldn't get a reading on them with the ohm-meter. You can't buy new versions of those switches as far as I can find. You can buy one switch that grounds a terminal to the car body when the door opens. But the way the buzzer is wired, that doesn't work, because the way the circuit is designed, neither side of the switch is grounded.

So I wired up a relay from a supply that I have around for just such occasions. This is a 3-pole, single throw relay, which is totally overspecced for this application but it means that I could do the job with one extra component. I soldered wires to the coil inputs of the relay, a short wire to go to the fuse box and a long one to go to the door pillar switch.

The left side of this photo shows an original switch (two pole, single throw, non-grounding) and the right side shows what I'm replacing the switch with (single pole, single throw grounding-only switch and a triple pole, single throw relay).

The setup on the right is big and cumbersome, but it works.

Here's the relay wired up and successfully tested. You can see the four wires that I pulled out of the door pillar and re-routed to plug into the relay.

The new grounding switch, wire from the relay attached, ready to install.

Door switch in and ready to go.

The final installation in the front of the car. The relay is duct-taped to the top of the gas tank, with a piece of cardboard for padding.

I wouldn't want to drive cross-country this way, but this is good enough to drive around town for testing.

Now there are definitely more efficient ways of doing this. The reason I used this monsterous relay is because I had it and it did the job all in one. However, two very small relays wired up together so that their coils were controlled by the door switch but they switched the two different output circuits would work just as well and be much smaller and easier to deal with, but I didn't have any more suitable relays in the house. The next time I get to radio shack, I'll pick some up and maybe improve this installation.