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  View original topic: Running a new + wire from main battery to fuse panel?
shizzon Fri Feb 08, 2013 10:46 am

Howdy

I am thinking of running a new 8AWG wire from my main battery compartment to fuse panel. My wire seems brittle, and the connectors on both ends don't look very good. Also, I'm trying to get better voltage to the headlights, and am hoping this will be one part of that solution.

I am looking for advice and helpful hints on how and whether or not to do this project.

As I understand, the wire goes down through the battery compartment, under the vehicle behind the fuel tank to the drivers side, and then parallels the main wiring harness, entering the vehicle near the driver's side headlight. Is this correct?

It seems like following this routing might be a PITA. Anyone reroute the wire differently? Or maybe it's not really that hard?

What about reusing the sheathing that goes over the wire?

What about upping to 6AWG -- is it worth doing?

Thanks!

bluebus86 Fri Feb 08, 2013 11:23 am

a new wire likley wont help the headlights much. If the connectors on the ends are bad, graft new connectors on. After i installed headlight relays (four each, one for each right and left one for each hi and low) I was getting near battery voltage at the lights. thus a bigger cable wont do anymore good. The installation of relays made a huge increase in light. the cable is not the weak link in the lighting system

shizzon Fri Feb 08, 2013 11:25 am

Hi,

I should have mentioned that I already have the headlight relays installed, but am seeing like a 1V drop when I turn on the headlights with the car running, iirc.

You're probably right though, just grafting new connectors is an easy and painless thing to try first!!!

sean

MarkWard Fri Feb 08, 2013 12:19 pm

I have completely upgraded the power supply to my fusebox from stock. I think you are on the right track. You should be able to run a wire up to the back of the fuesbox without going outside the van. The campers had a power lead from the fuesbox to the kitchen that snaked along the floor and into the facia underneath the driver's seat. Of course it had a sheath where it ran across the floor under the carpet and padding and a grommet where it passes into the compartment under the seat. You should be able to do the same on the passenger seat. Everything is working better, but on ours the battery is in the engine compartment.

crazyvwvanman Fri Feb 08, 2013 12:23 pm

You have the right idea but a better approach would be to run a new wire and use it just for the headlight relay power feed. That is my preferred solution and yes the headlights are then noticeably brighter. With local grounds added at each headlight to maximize the improvement of course.

The route I personally use is to run a #8 forward under the van, coming up behind the front grill and inside behind the glovebox. Then I mount the headlight relays right up there above the glovebox, with new fuses for each headlight.

Mark

shizzon wrote: I am thinking of running a new 8AWG wire from my main battery compartment to fuse panel. My wire seems brittle, and the connectors on both ends don't look very good. Also, I'm trying to get better voltage to the headlights, and am hoping this will be one part of that solution.

I am looking for advice and helpful hints on how and whether or not to do this project.

It seems like following this routing might be a PITA. Anyone reroute the wire differently? Or maybe it's not really that hard?

BillM Fri Feb 08, 2013 1:21 pm

Mark gave me this same advice a little while back. Only I used
6 guage wire because its what I have a few rolls of in my
shop. I installed a small six position fuse block and moved
my relays over next to it. I then made a new wiring harness
up to feed the lights doing my best to have as little connections
as possible. I used quality connectors that are weather proof
and require a specific crimper. The results were worth the work.

What initiated this project was even with having relays installed
there is still a weak spot left in the wiring. I can't recall what wire
and connector it was on the fusebox but it was one of the
wires coming off the relay for my high beams. It had burned
up right next to the connector the vendor who sold the relays
had installed. It wasn't the connector as I looked at my other
van with a relay kit from someone else and this same wire
was also looking like it had gotten hot. I wasn't running high
watt bulbs then either. Since installing the dedicated fusebox
and wiring I have upgraded the bulbs.

Good thing is I have two blank fuse spots that when the new repro PZ lights come out it should be a simple install and I am pretty sure the 6gauge
wire will be sufficient to handle the load. As the driving lights
must be wired to only come on with low beams per our
state laws it should be fine. I can't see the low beam/driving
lights on versus driving with the highs on that large of a difference
in the amount it draws. But just being a backyard hack I could
be wrong. That's why we're lucky to have people like Mark
that help us not burn down our vans.

PDXWesty Fri Feb 08, 2013 2:12 pm

Seeing a voltage drop when you turn on the headlights is normal. The increase in current draw causes this through the stock wiring as you mentioned. It's most likely coming from the wire from the alternator to the starter though. Add a new second #8 between the two and see what happens. You should see a noticible improvement in voltage drop.

BillM Fri Feb 08, 2013 2:20 pm

PDXWesty wrote: Seeing a voltage drop when you turn on the headlights is normal. The increase in current draw causes this through the stock wiring as you mentioned. It's most likely coming from the wire from the alternator to the starter though. Add a new second #8 between the two and see what happens. You should see a noticible improvement in voltage drop.

I think he has a zetec conversion and their harness includes
a heavy guage wire from the alternator to starter. That's not to
say his connections don't need a cleaning or the cable to
the battery needs some TLC.

Vanagon Nut Fri Feb 08, 2013 3:06 pm

As per Crazyvwvanman's comment, on my '88, I ran two fused and covered #12 wires (one for high circuit, one for low circuit) through an existing hole in pass. side battery box forward under carpet to relays, then out through new holes to headlights.

I figured since VW (or Westfalia?) ran a wire from the fuse panel to the kitchen appliances, running these wires under the carpet was ok.

Not contradicting Marks suggestion, but this is what I did.

On my '81, I soldered, shrink wrapped, tapped on a "new" OEM terminal on the 30 wire at the fuse panel. This has held up fine for the last 30-40 miles or so.

Neil.

shizzon Fri Feb 08, 2013 3:19 pm

That's right -- the bostig wiring from alternator to starter is new and beefy. My guess would be the wire between battery and starter is a bit crappy. It IS old!

So just to make sure I understand electricity correctly -- With the van running, if I measure the voltage across the main battery and see a voltage drop when turning on the headlights, that means its either a) the alternator to starter wire, or b) the starter to battery wire. Correct?

Assuming I don't see a voltage drop there, I could then measure the voltage at the 8AWG + wire coming into the fuse panel. If I see a voltage drop there when I turn on the lights, then it's THAT wire. Also correct?

PDXWesty Fri Feb 08, 2013 3:22 pm

Your procedure is correct. Which ever leg of wiring you see the highest voltage drop across is the weak link. You need to have current draw though while doing the test so make sure your headlights and maybe even the heater fan are running.

crazyvwvanman Fri Feb 08, 2013 3:48 pm

That is the proper method, actually measuring the voltage drop at each point from the alternator to the headlights. The engine should be running and alt led off. Then turn on headlights and measure at each point, then high beams and measure again. Then be sure to do so again with normal accessory loads turned on as well as headlights, like wipers on speed 2 and dash fan on speed 2. Any weakness will become obvious, and there will be weakness.

The early wiring and fuse panel 80-85 shows more weakness than the 86+. Running a #8 dedicated to power headlight relays helps both types though. For early type vans I have also run a #6 instead of #8 and moved the radiator fan power over to the new feed in addition to the headlights. The louder sound of the rad fan when this is done leaves no doubt that the potential for cooling is improved by this. I was first inspired to do this after seeing a few damaged early fuse panels at the rad fan fuse holder.

I have worked on the electrical systems of dozens of Vanagons, either adding upgrades or fixing problems, generally both. The same problems come up over and over. People complain about the poor headlights and think the answer is higher output bulbs when really they have a low voltage condition at the headlights. Relays help, local grounds help, adding a dedicated power feed helps. The dedicated power feed needs to be done safely so most people should leave it to someone who knows what they are doing.

Mark

shizzon wrote: ....
So just to make sure I understand electricity correctly -- With the van running, if I measure the voltage across the main battery and see a voltage drop when turning on the headlights, that means its either a) the alternator to starter wire, or b) the starter to battery wire. Correct?

Assuming I don't see a voltage drop there, I could then measure the voltage at the 8AWG + wire coming into the fuse panel. If I see a voltage drop there when I turn on the lights, then it's THAT wire. Also correct?

randywebb Fri Feb 08, 2013 4:35 pm

crazyvwvanman wrote:

I have worked on the electrical systems of dozens of Vanagons... The same problems come up over and over.

Mark - care to generate a list for proactive use by us owners?

crazyvwvanman Fri Feb 08, 2013 6:39 pm

To do so properly would take a lot of writing so I might one day write a small book. A chapter on known failures, one on known weaknesses by year, and one on known errors in the Bentley and Mitchell wiring diagrams. Another chapter for differences year to year, with problems caused by substituting parts from incompatible years, and so on.....

Mark

randywebb wrote: crazyvwvanman wrote:

I have worked on the electrical systems of dozens of Vanagons... The same problems come up over and over.

Mark - care to generate a list for proactive use by us owners?

Vinzanto Sun Feb 10, 2013 9:02 pm

So Shizzon where does that #8 connenct at the fuse panel?
I was recently tinkering around and I believe that wire was pulled from its connection and now I cannot figure out where and how it reconnects, any tips? It seems to follow the path you described verbatim.

Wonder if its the same wire? Mine is so brittle that there is practically no sheathing left but the number 8 tag was (almost looks brown not red but could not find a #8 BR wire in the Bentley). I asked for help on the wall and got nothing. You sound like your are in the closest predicament for advice.



shizzon Mon Feb 11, 2013 7:11 pm

By number 8 i meant 8 gauge wire. I'm not sure what you're showing there. The main (+) wire from the main battery to fuse panel is 8 gauge, and it's red. afaik its the same on all vans. others can chime in though.



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