SteveJ

Okay, where in Cumming?

If necessary... Datsun 510 120Y B210 240Z Side Marker Lamp Red Amber | eBay

If it keeps blowing, then we'll go into full diagnostic mode by pulling connectors to isolate the part of the circuit giving you problems. You wouldn't happen to own a multimeter and know how to use it by any chance?

Check the light sockets for corrosion. The side markers can get corroded as the gasket gets old and leaks. You might also consider moving to LED lights. They draw less power.

I don't have time to track down the origin of the green wire, but it goes all over the place, including to the turn signals. The battery signal isn't designed to go through a switched circuit. Go to How Stuff Works and search on alternator. I was going off of memory for the ignition signal. It is the white/black wire that is the ignition signal to the alternator. It should be connected to the wire at pin 1.

The black/white wire signals the alternator that the ignition is on. It will get that signal from the wire at position 1. The yellow wire is the battery sensing wire to the alternator. It is connected to the white wire because that is coming off of the fusible link.

If the connections aren't solid, the wire gauge is not relevant. A bad connection will act like a resistor and drop the voltage to your ignition.

I couldn't tell you without a spec sheet. I don't know how much they draw.

It's actually not a dumb question. There are two issues to consider: wire ampacity and voltage drop. The stock 240Z ignition system doesn't draw that much current. There just aren't that many components involved. So the 16 AWG wire is adequate. Voltage drop comes into play when you have DC voltages traveling along wire. I did a sample calculation for 16 AWG at 14 VDC traveling 10 feet in a circuit at 5 Amps. The voltage drop was 0.40 volts. (Voltage Drop Calculator)

You said you read the link I posted. It has much if not all of the information you requested. Please note the topics on the left side of the screen.

Start your research on the Z Car Home Page. You'll learn a lot.

The Mitty is just around the corner, April 25-27. I have been working with Grassroots Motorsports for a Z Car/Datsun car corral. It will probably be near the Suzuki Bridge. They are also working on getting free infield parking for the car corrals. If you're not familiar with The Mitty, it's a great vintage racing event held every year at Road Atlanta. In 2010 Peter Brock of Brock Racing Enterprises (BRE) fame was grand marshall. This year it's Brian Redman. They will also be featuring Formula cars this year. Go here to get ticket information: 2014 Speedfest at the Classic Motorsports Mitty Presented by Hagerty: Classic Motorsports If you want to join us in the Z car corral (and take advantage of the free parking if GRM can swing it), sign us to join us via Facebook at https://www.facebook.com/events/675525852490337/. You may have to "Like" the Georgia Z Club page first. https://www.facebook.com/georgiazclub If GRM says they will have free parking, I'll give them the names at that time.

I used the foam kits from Banzai Motorworks, not generic, and I believe they are worth it. It's easier to get the upholstery to sit right on the correct foam.

The path is not easy to trace, but the headlight circuit is protected by the black fusible link.

If you are worried that your crimped connections might fail...Sealed Crimp and Solder Connectors or Multilinkâ„¢ Sealed Crimp and Solder Butt Splice Wire Connectors and Ring Terminal Kits for a couple of examples.

Heck, Dave. I wasn't going to give him any suggestions on the headlights until he sorted out his charging system.

That passenger side frame rail looks pretty weak to me. Get some inside pictures of the pans, too.

I am curious. How long have you owned this car? Have you seen any instances of a previous owner re-wiring or altering the wiring in the car?

The plug I want you to find should be on the passenger side or maybe along the firewall. It will have the following wires: black/white, black, black/yellow and yellow (or yellow/black if the car was an automatic).

C-6 is under the dash. Of course, your ammeter is showing a discharge. You don't have the alternator hooked up properly, yet. The biggest problem you are having right now is that you aren't focusing on one problem. You are getting suggestions about two issues (alternator & headlights) in this one thread, and it appears as though you may be bouncing back between the two. Let's see if I can clarify the alternator issue for you. 1. You need wires from three locations going to a ZX alternator: Ground, battery, & ignition. 2. Your wiring harness was designed to utilize an external voltage regulator, therefore the harness requires some jumpers to re-route signals. 3. The white and yellow wires at that 6 pin harness should be jumpered together. That will give the new alternator the battery signal. 4. The white/black wire needs the ignition signal. Normally that would come from the wire at the #1 pin. According to the wiring diagram, that should be a green/red wire. 5. Since you don't have a green/red wire there, you need to get an ignition signal from somewhere else. The best alternative is probably the black/white wire coming off of the ignition switch. Trace that wire on the wiring diagram. One of the places it shows up in the engine bay is at the "Emergency Start Switch" that appears to have been deleted. If the harness was built to the wiring diagram, there should be a 4 pin connector in the engine bay on the passenger side with that wire. The thing that concerns me is that if you didn't have the green/red wire at the voltage regulator (or another wire in the #1 pin), I'm not sure how the charging system was working to begin with.

The three wire connector is for the AC. Have you tried to see if the green/red wire is on the C-6 connector? One of the issues is that the wiring diagrams show a seatbelt interlock relay system. I don't know when Nissan ditched it. You can find many threads about defeating them in the 74. The manual I downloaded from Xenons30 has too many artifacts to be truly useful. On the 240Z, the black/white wire from the ignition was joined with the white/black wire. Wiring that way may get the alternator working. Then you could focus attention on the lack of headlights.

Okay, so let's get this straight. The wiring diagram of the 75 identifies the wire from the engine bay harness going to the 1 pin on the voltage regulator connector as green/red. You say that wire was not present. I see a blue wire in the picture. Does it get 12 VDC when you put the key into the Run/On position? Does it lose 12 VDC when the key is off? Was the blue wire next to the green wire on the 6-wire connector? If so, that's the same as green/red. That would go to the white/black wire.

Okay, now I have more to go off of when I look at it later. That is if BeermanPete doesn't beat me to it.

What wires did you end up connecting to each other? Are any wires loose? Without that information, you will only receive guesses.

I noticed that, too.