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Wed Nov 19, 2008 4:28 pm

I am trying to wire things up so that my aux batt powers the interiors lights and radio. I gleaned that one solution is to tap the aux battery source right to B12. Here's what I did:

1: Disconnected main batt.

2: Found B12. There are two solid red wires on B, one heavy (B11), and one thin, B12. I cut B12.

3: I test continuity between the now-cut B12 wire and the red wire coming off the interior light over the water tank. Continuity. Good. Re-connected the battery and noticed that the clock didn't power up. It did not. Good deal:

4: I wire up my new lights off of the lead coming from the interior lights. Then I connect my aux battery and...nothing. No lights. B12 does not power my interior lights or radio after all. I connect the main battery and...the radio and interior lights work.

It turns out that the only thing B12 powers is the CLOCK, as far as I can tell. What the hell? I mean, I would like to undertand what is happening here. The only thing I can figure is I didn't cut B12 but rather the wire sent power to current track 47. Oh, crap - that's what I did, didn't I? Is that why there was continuity from the cut wire and the lights?

I'm looking at page 97.76 and my brain hurts, but I think that's what happened.

Re-attaching B12 won't be difficult because I actually added more wire in case I wanted to re-connect.

Okay. I'm posting this even though I think I figured out what happened, so maybe somone else can learn from my mistake.
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Yes, yes, I hear you. You may ask, why do I not just run a line to the cig lighter wire and yank #3 fuse. Well, when I first got my Vanagon, I think I might have powered come gauges off of the cigarette lighter wire including my volt meter. This was a long time ago, and EVERYTHING under the dash was alien to me. And now there is a nearly impenetrable console bolted to the dashbaord. The joke's on me!
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So here's what I'm gonna do. I think. I'm gonna try to find B12 again.

I'm sure it's pretty painful for you people who know what they're doing to read the misadventures of left-brain blunderers such as myself, but at least try to extract some entertaiment out of it. :lol:

Wed Nov 19, 2008 5:54 pm

It's definitely not pain I'm experiencing.

Wed Nov 19, 2008 6:20 pm

I guess the easy and elegant approach is not good enough?

There is no need to cut any wires or access B11 or B12.
Simply remove fuse 3.
Then put a male spade on the end of a fused feed wire from the aux battery.
Plug the male spade into the lower socket hole where Fuse 3 was pulled from.
DONE

This powers everything that was on fuse 3 with aux battery power on 86-91 Vanagons.

Mark

[quote="deprivation"]I am trying to wire things up so that my aux batt powers the interiors lights and radio. I gleaned that one solution is to tap the aux battery source right to B12. Here's what I did:

1: Disconnected main batt.

2: Found B12. There are two solid red wires on B, one heavy (B11), and one thin, B12. I cut B12.

3: I test continuity between the now-cut B12 wire and the red wire coming off the interior light over the water tank. Continuity. Good. Re-connected the battery and noticed that the clock didn't power up. It did not. Good deal:

4: I wire up my new lights off of the lead coming from the interior lights. Then I connect my aux battery and...nothing. No lights. B12 does not power my interior lights or radio after all. I connect the main battery and...the radio and interior lights work.

It turns out that the only thing B12 powers is the CLOCK, as far as I can tell. What the hell? I mean, I would like to undertand what is happening here. The only thing I can figure is I didn't cut B12 but rather the wire sent power to current track 47. Oh, crap - that's what I did, didn't I? Is that why there was continuity from the cut wire and the lights?

I'm looking at page 97.76 and my brain hurts, but I think that's what happened.

Re-attaching B12 won't be difficult because I actually added more wire in case I wanted to re-connect.

Okay. I'm posting this even though I think I figured out what happened, so maybe somone else can learn from my mistake.
_____________________________________________

Wed Nov 19, 2008 8:30 pm

tencentlife wrote: It's definitely not pain I'm experiencing.
Crap - I was hoping you'd pass on reading this one.

Wed Nov 19, 2008 8:56 pm

Yep male spade in fuse 3 works for me too, not sure about your other problem. :?

Thu Nov 20, 2008 8:34 am

What happened was I sent power to track 47 (or 53, I think, in some Vanagons) which comes off of pin B12 as well.

As for my "other problem", well...I probably shoudln't be working on cars but here we are anyway. :)

Thu Nov 20, 2008 10:31 am

Andrew, if your aim was to power the interior lights and clock but NOT the dash cig. lighter, then you would want to remove B12 from the back of the fuse panel and patch your aux power in there. But, and I don't know how you're missing this since it's right there in all the '86 diagrams, there are two, count 'em, small-gauge red wires coming off B12. It sounds like you cut and patched into the one that only powers the clock (track 71-to-47 on p.97.76; track 79-to-53 on p.97.93). You would have to cut and then connect to BOTH wires to get the interior lights onto your aux batt power feeder. That is if you want to power clock and lights but NOT the lighter.

If you want to power clock, lights, AND the lighter, of course you know my preferred method for that; direct wire to the lighter. Alternately, you could patch onto B11 behind the fuse panel (not cutting it from the panel connector, just add the aux feeder to it) and remove fuse 3. That powers the lighter along the heavier red B11 wire for the higher current the lighter can draw, while also backfeeding B11 into the panel where it is common with B12 to the clock, lights, etc. This has the same effect as just taking your aux feeder directly to the lighter positive post, you're just connecting to the same circuit in a different place.

Now some prefer just patching into the fuse connector from the front, and that's basically OK and will power clock, lights, and lighter. But, no one acknowledged the other problems you mentioned in your initial post, about having some gauges powered off the back of the lighter and so on. Really, you ought to reroute the power for those items so you're not adding a fudge to a pre-existing kludge. But that being as it is, a decision that is up to you, to accomplish your initial goals as stated you would want to cut and patch into BOTH B12 wires from the back of the panel.

If you decide to repower those other kludged items, here once again is the power map for the panel:

This applies to the late, '86-on fuse panel only:

When you want a power supply for something, there are unused pins on the back of the main relay panel for most anything you'd need. On the left end (installed position), there are 6 pins in two rows labelled "P". These are all #30 pins, battery direct, unswitched, unfused. They are good for fairly heavy consumers. At the other end are ten pins labelled "G". These are hot under various conditions and can be used to power accessories. You can patch into the panel at whichever pins do the job for you by just plugging on a female spade terminal. It is always advisable to use a fuse inline from any power source to protect your device and wiring.

I'll list them according to the diagram. Where power is via a panel fuse, I've noted that with the letter "S". Always verify with a testlight or VOM before hooking up:

G1 & G3- X-bus load-controlled power (hot when ign. on, goes cold when starter operates) via S12
G2 & G5- #15 ignition-switched power via S18 (this is the ideal power source for extra instruments)
G4- D+ (alternator trigger circuit) via alternator warning LED
G6-dead end
G7 -headlights power
G8 -dimmer-controlled panel lighting power (to light your extra gauges)
G9 -parking lights power via S20 (for your low-rider under-chassis lighting, ese!)
G10- hot when windshield washer pump runs (headlamp washers, anyone?)

The reasons I personally don't like patching into the front of the panel via the fuse sockets are that A.) if that's elegant, I have a haircut you might want to try on, and B.) lighter sockets were designed for brief intermittent hi-amp use, but nowadays they get used for all sorts of plug in accessories they weren't designed for, like small inverters, and ganged plugs handling multiple chargers, etc. I would rather have a fused feed with heavy wire and a solid direct connection to safely handle the kind of ongoing use that the socket is more likely to get these days. In my experience you don't want to use more than about 10A thru one of these for very long, so I would fuse the feeder at 10 or use 15 if you have the lights and clock on the same circuit.