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Mon Nov 02, 2009 11:00 pm

The above link to the wiring diagram is wrong for your '73 SB. Try this one:
http://www.thesamba.com/vw/archives/info/wiring/73-only113wiring.jpg

Look at the fuse in column 40. That's #12 fuse and powers the following items:
turn signals (turn signal circuit runs thru the E-Flasher switch terminal #15)
indicator lights in the speedo + fuel gauge + brake warning
safety belt system

I would suggest disconnecting everything from #12.
Make a short jumper wire that you can run between the #12 fuse and each item, in turn. When you connect something and it pops the fuse, you have found your short.
Since leaving your turn signal on #12 didn't blow the fuse you should be ok there. BTW, #12 fuse is an 8A fuse.

It also sounds like your turn signal light or fuel gauge may be wired wrong.
Note that the speedometer case is grounded so that the lights that illuminate the speedo at night ground thru the case.
The turn signal/oil/gen lights do not share a common ground, but instead share a common 12v+. This common 12v+ terminal runs back to #12 fuse for power. It is not uncommon for someone to mistakenly wire this common connection to ground.
From the factory, switched 12v+ is usually a black wire and ground (-) is almost always a brown wire.

Fri Nov 13, 2009 12:28 pm

hazard realy with one from oe vee dub, the first one they sent was smashed and the second one makes a wierd buzzing noise whenver the key is on. The buzzing stops as soon as i employ the turn signals or harzards. Anybody keen on what this buzzing is?

Fri Nov 13, 2009 1:51 pm

Ok, it doesn't sound to me like you have any component problems (except perhaps the hazard switch). If the lights blink then the blinker relay works.

There are TWO power wires that go to the hazard switch. from fuse 12, a GREEN wire goes to terminal 15 on the hazard switch. That operates the turn signals. A RED wire goes from fuse 8 to terminal 30 on the hazard switch, this operates the hazard flashers.

Another green wire goes from terminal 8 to the fuel gauge (top of the speedo) and then through a double spade on to the bottom of the speedo and the warning light strap (the barrel of the three bottom lights).

Fri Nov 13, 2009 1:56 pm

Oh, and I presume that you've gone through and checked with the diagram that the COLOR of each wire is connected to correctly NUMBERED terminal on eatch switch? Reversing two connections could easily cause some of your problems.

Fri Nov 13, 2009 2:02 pm

all my connections are correct. ive been checking them over and over again for 2 weeks now.

Fri Nov 13, 2009 2:17 pm

i take that back. obviously ive screwed something up. Now the car wont start like theres no power to the ignition. The buzzing from the hazard relay turns off when i switch on the headlights. And my tach is all screwy. Any ideas?

Fri Nov 13, 2009 2:33 pm

jwagner wrote: i take that back. obviously ive screwed something up. Now the car wont start like theres no power to the ignition. The buzzing from the hazard relay turns off when i switch on the headlights. And my tach is all screwy. Any ideas?

If it were me I'd take a step back and start checking everything, assuming that nothing's right.

Disconnect the negative battery cable. Get your multimeter, set it for the big current setting (10A). Key off. Touch one wire to the negative battery terminal, touch the other to frame. You should get 0A. Turn the key on. Then touch use 10A again from frame to neg terminal. You should get whatever the coil plus carb solenlid and electric choke draws, 3A or something like that. Go to the back, disconnect the black wire to the coil and make sure it's not touching anything. Go back, key on, check current. Should be 0 again. Go like that, first through all the always-hot unfused circuits, then through the keyed unfused circuits. Once you know where everything is going, and there aren't any shorting/bad connections, then go through the fuses one by one and make sure they're only connected to what they're supposed to be.

Fri Nov 13, 2009 3:23 pm

I'm sorry to be worrisome about this. However, there are several wires in the Beetle's wiring system that NOT FUSED ANYWHERE. They include the power to the coil and the starter. If you've changed something that made your car not start when it did before, you're in very real danger of creating a connection that could short out and burn wires, melt/burn wires down inside the car, or at worst, start the car on fire.

My recommendation is that you go RIGHT NOW and disconnect the negative terminal of the battery, and then sort things out from there.

I can write you a procedure that will help you track this down. However, I'm flying to a conference tomorrow. I can work on my checklist during the flights, but I won't be able to get them to you before Saturday night for sure, and maybe later than that.

There are certainly other folks on thesamba who can help you better than I. Whoever it is, this is going to take some time to sort out.

Fri Nov 13, 2009 3:42 pm

a list would be great. I dont have a garage to work in, and by the time i get out of school i only have 3 hours of daylight which go by fast. Not to mention its only like 50 degrees, usually less as the day drags out. Needless to say its hard to get work done. Everything i take out i have to put back in the car and the whole situation is a drag. Im going to talk to the schools shop teacher and ask him if i could occupy some space in there for a week so i could spend every day after school trying to sort this out. No distractions, no schedule. Only trick will be getting an imoble car to the school :? Or who knows, maybe ill be able to figure it out tomorow after work.

Fri Nov 13, 2009 4:32 pm

jwagner wrote: Im going to talk to the schools shop teacher and ask him if i could occupy some space in there for a week so i could spend every day after school trying to sort this out.

Your sig says "DD"; does that mean daily driver? I presume not your only transportation?

I almost hate to say this and delay you, but I'll be in Illinois (Urbana) on business in early December. I could arrange to drive up for most of a day and help you, if that would be useful (It would have to be a weekend day, probably a Saturday). I could bring tools, manuals, diagrams, spare fuses and connectors and the like.

I'm not an auto mechanic or an engineer of any kind, but I like working with wiring (my background is in experimental physics; wiring is part of the job). Send me a personal message on thesamba if this would be useful and you're interested.

Sat Nov 14, 2009 2:36 am

Your last post two weeks back said your problems were only with the #12 fuse blowing. What changed to add starter, headlights and tach to the problem list??

Here are some basic aircooled VW electrical basic concepts that may help you in your troubleshooting...

Look at the '73 SB wiring diagram.
http://www.thesamba.com/vw/archives/info/wiring/73-only113wiring.jpg

In this diagram, electrical power generally runs from top (+) to bottom (-). The black line that runs across the top of the yellow bar at the bottom of the page represents chassis ground (-).
Power runs from the battery (+) post thru various items, but always ends up at the bottom of the diagram, ground (-).
The fuses are NOT positioned on the diagram in any specific order. They are numbered as they are seen in the fuse box from left to right. #1 is the left most and #12 the right most.

You need to determine which edge of the fuse box is the INPUT. Note that some fuses like 3-4, 5-6, 8-9, 11-12 are connected at the top end in the diagram by a black line. This indicates they share a common connection. If you look at the back of your fuse box where you plug wires in, you will notice that on one side of the fuse box some fuses have a thick brass connector between the terminal of two fuses. This is that shared connection. This edge of the fuse box is INPUT. A single power wire connected to this INPUT side can power two fuses (eg. a single yellow wire to the INPUT of fuses #3 & #4 provide power for both the left and right low beam fuses/lights).
Remember that the fuses are numbered in reverse (12 --> 1) when you are looking at the backside of the fuse box.
The reason this is important is that if you connect the input to the wrong side, you may have multiple circuits running off a single fuse instead of two or three. And connecting an output wire to the input end of the fuse means the circuit is NOT FUSED.
Some circuits like the starter and ignition circuits are NOT fused.
Other circuits like headlights are fused half-way thru the circuit. So if you connect one of the headlight wires to ground and don't realize it, you can start a fire (because the fuse won't blow).

If you want to start from scratch, you should confirm you have the proper diagram for the fuse box you have. There is always the (small) possibility the PO replaced the fuxe box w/ one from a different year.
As I mentioned, for the '73 SB, the 3-4, 5-6, 8-9, 11-12 fuse "pairs" should share a common connection on their INPUT edge. Check your fuse box to make sure this is the case. If it's NOT, we are using the wrong diagram to troubleshoot your problem.

Sat Nov 14, 2009 2:42 am

jwagner wrote: time to take the dash back out and retrace the circuits. Kinda wish i had a standard bug right now.

I know what you mean, I just pulled the dash out because the PO already did the unbolting part and it's oversprayed like mad and the wiring just kinda makes you want to hide in the corner.