TomoHawk

I would use a separate circuit for the 100W lamps, but the control would be through the high beam line and one control switch in the cabin.

Would it be a good idea to put in a small drain hole with a tube next to the weatherstrip?

Yeah, I thought I might be over-estimating the current requirement of the headlamps. I also have a set of 100W Cibie driving lamps I think I will mount eventually (actually they have 55W bulbs, but I think I will go to 100W.)

I'm leaning towards the Weather Pak 4 pin square connector. I just have to figure out who has my fancy crimp tool.

If you go the same connector the 240Z uses for the headlamp harness, would it make sense to then buy th MSA headlamp relay kit, and avoid all the fabrication?

Since you can't get the original Yazaki connectors, I searched for some well-designed connectors/pigtails that are available today. SummitRacing lists some electrical harnesses and adapters, but no pigtails or connectors. The best connectors I found were WeatherPack connectors, which are sealed, interlocking, and made for different gauge wiring. I chose 12Ga., to handle the current for headlamps (20A total.) Weather Pack 3 Pin Sealed Connector Kit 12-10 GA If there are suitable alternatives, please mention them! BTW- Yazaki has a website: http://connectors-catalog.sys.yzk.co.jp/ but I didn't see anything familiar to S30 there.

I got my 6-position MP6N connector from cycleterminal. It looks fairly similar to the tail lamp connector, but I'll have to go out to the car to check it, maybe Friday.) If it's still not the same connector, I can use it for the center console. Why did Nissan need all those smaller connectors (and several pairs of bullet connectors) for the switches, and the lamps (shifter, ash tray) when they could have combined it all together? It's probably some kind of production simplification thing.

Well, since there really is no "plug-and-play" actuality for the '78, you are modifying the stock wiring nonetheless, so you may as well do it right or in an improved way. OTOH- if you are adding some lamps, like fog lamps or driving lamps, that second (unused) fuse would come in handy.

That traditional diagram should be improved to run the current from the fusible link to the relays instead of to the switch- it's overkill for what you need to turn on the relays. At least substitute a fuse for the fusible link, or split the wire just after the fusible link to supply both the lamps and the switch. I keep wondering if there is a way to put in a fail-safe condition in case a relay fails, so it defaults to low beams. I suppose you could keep a shunt handy to bypass the relay, as well as a spare relay.

I like Sarah's use of SPST relays. You will only need two, and they are wired parallel, instead of serially, so unless you turn the headlamps on, nothing gets power. Also, if one fails, the other can still power the lamps, but you will lose the function of either the high or low beam, depending on which one fails.

This is not possible wt the 1978, because the headlamp connectors are not available. the only possibility is to find some pins that fit the stock headlamp connector, which is more probable. What is the AC circuit?

This is a table I found. What do you think of its information? http://www.engineeringtoolbox.com/wire-gauges-d_419.html

I've been reading that the relay mounts are interlocking. Is that correct? Does it add any strength to a group of relays so the group can be mounted to a bracket or bulkhead?

Adding relays is so simple, but opening up the taped wiring and finding the wires, and even getting a good, clean/uncorroded bare wire is something different.

The MSA one is not for the 280Z, so it will not "plug-and-play." It won't work with H4 bulbs either.

Is there any place to get a quality headlamp harness with a relay, that's not from MSA?

that is what I mean by a double-ganged relay, with the SPST.

If you wanted to wire a relay into the headlamps, could you get a SPDT relay with center off? Otherwise, You'll need to double-gang relays like an interlock system to cut the power to the whole headlamp circuit when not in use. All the wiring diagrams I've seen so far use a SPDT relay for the low-high beam switching, but the circuit stays always HOT, which would make me nervous when not in or around the car. What's there to cut the power so you don't drain the battery or start a fire? A center-off relay would make things really simple.

Here is an example of the connectors I got from the JY. This one has 4 pins, and as you will see, there is an internal seal (the red rubber ring.) While it would probably work for LED lighting, I'm not too sure this would work as well as I'd like it to work for me. This connector was not easy to take apart, and when I tried to push it back together the pins were bent apart and couldn't be straightened. I will have to toss this one in the trash and consider something else, probably a lighting connector instead of an engine sensor connector.

The picture with the ears was from the website, to show the plug was a similar shape. BTW- are you aware of the the new heat shrink tube with solder? It appears to be a viable way to make quicker butt connections on an automobile with sealing and good 'pull-out' strength. The only drawback is that they use new shiny copper wire instead of our corroded copper stuff. Video: Amazon item: http://www.amazon.com/Shrink-Solder-Sleeve-Crimpless-Connectors/dp/B00IEFOCRK

Mr. Ford hath provided several connectors; one 4-pin from an Oxygen sensor, and a few three-pin connectors.

Oh, Duh. The three-pin connector is for the front turn signals... I'm off the to JY!

Yeah, I think you're right. What would you call that? It's not the usual 4-pin connector, like the one for the vacuum solenoids. I also need some 2-pin sets for the turn signals- mine are getting funny. I was thinking that I might have to go to the JY to snip some headlamp connectors from a modern car... Then I could even get a set of spares, or order spares. I gotta get my time machine to work right some day soon.

Yes, I think cycleterminal has the headlamp connectors: http://www.cycleterminal.com/yazaki-ypc.html

I have not noticed any ears on the tail lamp connectors, but I think the ones for the gauges have them. Yes, I think those will be compatible, and I could even use one for the new center console wiring. Thanks for the help. If only you could get the 3-pin round connectors for the headlamps. Then you could make a truly 'plug-and-play' relay setup for the headlamps, instead of sacrificing the factory headlamp connectors.