TheSamba.com :: View topic - switched power without key-in warning circuit

Fri Nov 21, 2008 9:13 am

My '86 WWW does NOT have the key-in ignition switch warning buzzer circuit that many have recommended as an elegant way to get switched power to a modern amp-sucking stereo unit. At least I'm pretty sure it doesn't: The seatbelt warning cucaracha doesn't come on until I turn the key to the on position, at which point the o2 and alternator lights also come on.
I don't really want to put in a separate dashboard switch (but I will if I have to), so I have questions, like:
Is it likely that there is a key-in circuit, even if the seatbelt warner doesn't use it?
Is there any other way of rigging something similar?

Perhaps this info is somewhere in the Bentley, but I haven't been able to find it. The 85-86 WWW vans seem like a transition setup, especially in the electrical system, so I'm often lost when trying to find info like this. My apologies if I overlooked something obvious.

Fri Nov 21, 2008 9:39 am

Could this be a faulty (although doing most of its job) ignition switch? Or a bad buzzer? I've never seen a Vanagon that wasn't wired this way, though I haven't done an extensive survey. I've changed two ignition switches, one on my own and one on someone else's Vanagon, so if it were me, I'd try an ignition switch if you couldn't track down the wiring any other way. The switched can be had for less than $4 at autohausaz, and can be changed in 20 minutes. If you just want to do a test, I think you should be able to pull off the column cover and put the wiring harness on the new switch without taking the old one out, and then push on the hole in the new switch to simulate the key in the other part (I know this isn't the clearest description, but I hope you get the idea.)

Ed in CT

Fri Nov 21, 2008 10:10 am

Some stereos have a depower function so they can be wired into a full time 12v source. On mine I just have to hold the off button for 3 seconds or so and the units drops to a minimal amp draw. Read your instructions.

Fri Nov 21, 2008 10:41 am

I found this site with some information about using your Key In Switch to power your stereo. Not sure if this is helpful to you, but it is a good way to power your stereo with the key inserted.

http://www.weidefamily.net/vanagon/

Look under the Electrical Tab and there is a file for using the Key inserted circuit to power your stereo. Hope this helps and much thanks to Brent for all of his knowlege and his website.

Fri Nov 21, 2008 2:23 pm

Look at the backside of the ignition switch wiring connector plug. There is a small-gauge gray wire with black stripe. This is the "SU" key-in warning trigger wire. Probe the back of the connector and if that wire goes hot when the key is inserted, the switch works as normal, regardless of whether your warning relay is working or is even present.

You can use the SU circuit to either directly power a low-power stereo head, or to trigger a relay to power a higher-power item.

If your stereo is connected to a separate power amp, then the stereo's internal amplifier section is inoperative and it is OK to power the stereo head directly from the SU circuit so long as the power amp is powered independently. If you use the stereo's internal amp, you would be wise to instead use SU to trigger a power relay. This depends on the configuration of the stereo's power inputs. The SU contactor in the ignition switch is very small so it has little power capacity; as a conservative guess I would keep it well under 5A to be safe.

Sun Nov 23, 2008 12:47 pm

Well, I did as the wise $.10 suggested and confirmed that the gray/black wire from the ignition switch does indeed come alive with the key in, even though the cucaracha doesn't start until the key is turned.
So now I'm ready to add a relay for stereo "acc" power. I've got a number of unused relay locations on the fuse block (e.g., location #6) that look very much like they are just waiting for me to plug in a relay, but (and here's the stupid question....watch for it, watch for it....) I have no idea how to connect any wires to any of the female relay connectors on the fuse block.
What am I missing?

Sun Nov 23, 2008 1:30 pm

You're missing that all the connections to the panel's built-in relay sockets are internal. You don't wanna go there. It might be possible to backtrack all the pins on a vacant socket and patch into those circuits elsewhere, but it would take some study, and I rather doubt there is a solution there; I would have to look. How good are you with the wiring diagrams?

You can get relay sockets that have a little dovetail projection that will slide into one of the dovetails atop the panel. That's about as close as you're likely to get for emulating stock mounting. I never searched for them so no idea where to get them, but they are available and I'm sure someone will chime in to say where.

Otherwise it's locate the relay somewhere out of the way and run your own wires to it.

Sun Nov 23, 2008 2:02 pm

Relay socket 6 would be a logical choice of the empty sockets available. The problem is that it uses a special 4 pin connector on the back and I have no idea how you would find the plug to match it. Page 97.80 of the Bentley shows relay socket 6 and the 4 leads from it going to pins L1-L4 on the back of the panel. Page 97.68 shows the back of the relay panel and in the upper left has the L block and it's 4 pins labeled, 2 smaller outer pins and 2 larger inner pins for high current.

You would need the special 4 pin connector and 2 of each size pin to fit it. Then you would need to know how to hook that up to do what you want it to.

Mark

BoneStock67 wrote: Well, I did as the wise $.10 suggested and confirmed that the gray/black wire from the ignition switch does indeed come alive with the key in, even though the cucaracha doesn't start until the key is turned.
So now I'm ready to add a relay for stereo "acc" power. I've got a number of unused relay locations on the fuse block (e.g., location #6) that look very much like they are just waiting for me to plug in a relay, but (and here's the stupid question....watch for it, watch for it....) I have no idea how to connect any wires to any of the female relay connectors on the fuse block.
What am I missing?

Sun Nov 23, 2008 2:43 pm

Thanks again, Ten, and thanks to you Mr. Crazy.
So to keep it maximally stock it looks like I need either a dovetail relay socket or a special four-pin connector, neither of which I have.
Ah well. Something else to search for.

Sun Nov 23, 2008 3:14 pm

The relay socket should be simple to find. I get used ones from various VWs at the junkyard. They slide and lock into the top edge of the relay panels. With a small flat screwdriver tip or such you can release the locking tabs and slide it back out. The same relay sockets are sold by various vendors in their headlight relay kits so you could get a kit and only use one relay of the pair or inquire to see if they will sell you what you need. Terry Kay has that stuff and sells here all the time. Some of the used ones I get also have a fuse mounted to the socket.

Mark

quote="BoneStock67"]Thanks again, Ten, and thanks to you Mr. Crazy.
So to keep it maximally stock it looks like I need either a dovetail relay socket or a special four-pin connector, neither of which I have.
Ah well. Something else to search for.[/quote]

Sun Nov 23, 2008 4:27 pm

Go to 12v.com . They will show how to build a retained power supply with three relay's and a diode. It works great and the building instuctions are straight forward.
I've got two of them in use.

Stacy

Mon Nov 24, 2008 9:33 am

Hey, waddya know; the relay sockets (aka "relay plates", part #161937501b) are NNLA (NOT no longer available) and so I ordered three from my local VW dealer parts counter. At $11 each, certainly more expensive than from the junkyard, but at least I can feel like I'm doing my share to help keep our parts on the NNLA list.