Captain Obvious

Cool. If your car is wired as per the diagram from the 70 Owner's Manual, then you already have headlight fuses hot all the time. So I believe the answer to the question "With the set-up in my car (per the wiring diagram from the 70 Owners Manual), what do I need to do -- if anything -- to make my two headlight fuses always hot?" is "Nothing." I believe you're good to go in that respect. You can double check that by pulling one of the short pigtail headlight connectors off in the engine compartment and probing the R or R/Y wires while having the headlight switch in the OFF position. If your car is wired like the 70 manual, then the R and R/Y wires to the headlight pigtails should be hot at all times, while in the later cars, those two wires would only be hot when the headlight switch is in the #2 position. And I wasn't there when they designed the system, but I wouldn't be surprised if that's why they changed it in later years. It's less safe and less fault tolerant to have those wires hot at all times than to have them only powered when the lights are on. I'm not sure that's why they went away from that early scheme, but if I were designing the wiring for the car, I would have tried my best to never have anything hot at all times unless absolutely necessary. It's just safer when it's dead. So else can we do on the headlights? Are you OK at this point? Current round of questions answered? On Edit - And BTW - Thanks for culling the 70 diagram out of the owner's manual. I've got the whole thing in pdf, but it's much more convenient to have the wiring diagram pulled out and separate in it's own file.

Namerow, OK, I had a chance to look into the early years. First, You nailed this objectives of the modifications to the combo switch: 2. Make the 'Headlamp' fuses always hot However, I would make one change to the other objective (because the dimmer switch always did switch to ground). I would change the other objective to: 1. Make the Dimmer Switch switch to ground only when the headlights are on and not make any connection at all when off Second, I found a wiring diagram in the 70 Owner's Manual (not FSM, but Owner's Manual), and it appears that what's old is new again because the 70 cars are wired such that the above two objectives are already achieved. The headlight fuses are always hot, and the hi/lo select has three states: low beam connected to ground (R/B high beams connected to ground (R/W) no beams connected to ground (OFF) Third, I found the wiring diagram you referenced in the 1971 supplement manual and there are two diagrams in it. "Basic Model" and "Late Model". The "Basic Model" is wired like 70 version in that the fuses are always hot and the hi/lo beam select switches has three states. The "Late Model" is wired like all the subsequent years through 78 in that the fuses are only hot when the combo switch is in the #2 position (headlights on) and the combo switch always connects one of the beams to ground regardless if the headlights are on or not. Are we both on the same page so far?

Happy Canada Day!!

My unicorn and I will be there on Thursday July 16th. Late afternoon/Evening.

Namerow, Yeah, I wouldn't be surprised if there were some differences with the earlier cars and I probably should have accounted for some of that. Sorry for any potential confusion and I'll take a look at the older wiring diagram and see what I come up with.

charliekwin, The progress looks great. One thing though... I don't like the positioning of the lower spring on one of your rear brake setups. Looks like the spring is bent around the adjuster mechanism and that shouldn't need to be the case. I can't tell what the problem is, but if it's together correctly, everything should fit comfortably. I'm not sure why the one side looks weird: One side looks fine, but the other looks questionable.

Actually the stock system makes it impossible to do what you want to do. You can never have heated, conditioned air to the defrosters. Ever. Because of the design of the air flow system, the only location to ever exit conditioned air is from the "vent" locations. You can never have conditioned air come out of the defroster holes or the floor holes. Dash vents only. So while it would be relatively easy to bypass the electrical portion of the system and add provisions to make it possible to turn the compressor on regardless of the slider position, you simply cannot control the air exit position the way you really need it. And not only that, but when in the "DEF" or "HEAT" positions, the dash vents are completely closed off, so you'd freeze up your evaporator because you wouldn't have any airflow through it. So the best you could do is modify the electrical portion to allow independent control of the compressor and then put the slider in the BI-LEVEL position. That way you could get heated air on your feet and some conditioned air out of the dash vents. That air would mix inside the passenger compartment through convection currents and the end result might defrost the windshield. Might be better than stock, but certainly not as good as modern cars.

Bummer. I doubt there's any recourse from the company from which you purchased the wheels. You've probably had them longer than any warranty period, but it's not like they've seen any significant mileage. Bad enough that you could see it with the naked eye... How does that make it out of the factory?

Wow. I would have expected a bent axle or hub mounting plate if anything. A bad wheel? That stinks! Were those new or did you buy them used? Also, I assume they checked all four and only that one corner had an issue?

Back EMF works for me as well. I've heard it called lots of different things. Whatever works!

I can't help with your question about potentially different mechanical ranges of the heater valves between A/C and non-A/C cars, (so I probably shouldn't be in here at all) but in the spirit of the internet forum... All of the temperature control valves are mechanically actuated with a cable. The vacuum operated valve that you have as part of your A/C system is in series with the temperature control valve and it's purpose is to completely shut off all water to the heater core the instant you put the control lever into any of the A/C positions. Datsun is essentially saying "Nobody in their right minds would ever want to have warm air blowing on the windshield or floor while the A/C is on, so we'll just take that option out of the hands of the occupants. We'll just turn off all the water any time the A/C is on." I disagree with that design decision, but I wasn't there when they made that call.

Chas, Why do you think it would be necessary to open the "dimmer" relay to cut the resistance? That resistor is in parallel across the coil windings to limit the inductive kickback voltage and compared to the coil resistance, I bet it's a relatively high resistance. Like maybe an order of magnitude? It would "waste" a small amount of power when the relay coil is energized and be completely innocuous when the coil is off. I don't understand why you cant just leave the resistor alone and use it for it's intended purpose?

The form factor and pin-out should be the same for any manufacturer, but I can't attest to the inclusion of a diode inside to squelch the inductive kickback. Sometimes an internal diode available as an option from the manufacturer. In other words, sometimes you can buy the exact same relay in two versions... with or without an internal diode.

Hi Tamo, As SteveJ mentioned above, the polarity across the coil winding only matters if there's a built in diode inside the relay in parallel with the coil winding. I can't attest to the contents of all of the relays in that form factor, but I can tell you that the ones I messed with did not have a diode inside and the coil polarity did not matter. Also, on your sketch showing the starter relay, I think you swapped the C4 and C7 designations and the destination labels for those connections. I think what you have labeled as C4 "To fusebox" is actually C7, and vice versa. And one last thing... If you're doing an internally regulated alternator upgrade at the same time as the starter relay it is convenient because the original external regulator already has some of the connections necessary for the starter relay. In other words, the external regulator already has "always hot" and "ground" connections that can be re-purposed to power the starter relay system once they are no longer needed for the external regulator system.

Haha! I didn't even notice the mispelling until you mentioned it. Don't care. Either works. Mike, I would love to help out around here, but I'm not sure I'm reliable. I'll send you a PM and we can talk about it some more.

I've not investigated the differences between years, but I gotta believe that if you ported the entire system over it should work. I also don't know if there were any performance or emissions tweaks from one year to another. At that point in time, electronics technology was changing pretty quickly and I wouldn't be surprised if there were some changes between years. However, a perfectly working 75 system is still better than a questionable 77 system though, right?

Haha! Yeah, a couple thousand! Good luck at the alignment shop and here's to hoping that wobble was just the tire lettering.

I went to the Maple Syrup Museum in Montreal! I also had poutine. I wasn't bowled over.

I was trying to ignore the irregularities in the tire and focus on the wheel, but it was difficult. Bring it over, I'll check all four for ya. I got an indicator on a mag base with a flexi-wand.

And less than a block away from the Peabody is this place. I'm not recommending we go... In fact, I'm recommending we don't. I'm just thinking we need to keep Blue and his crew far from this place. We don't want any international incident.

I don't know what GM is thinking with their label nomenclature, but there's nothing special about either of those two relays. One of them is SPST and the other is SPDT: http://www.ebay.com/itm/like/161716893434 http://www.ebay.com/itm/like/111673850865

Matt, It's awesome the way your car turned out. I enjoyed the videos as well! One thing on the video... When you had the camera mounted behind the left rear wheel, is it my imagination, or are you getting a little wheel wobble? Might just be the raised lettering on the tire tricking the eye, but I'm thinking you might have some runout on that rear hub. I'm probably just imagining things, but you might want to stick an indicator on the corner and see what you get?

And to test the possibility of a primer button helping your hot-start, you could just pull the starter solenoid wire and run the pump for some time with the key in the START position. Then after you're convinced that the fuel lines have been purged, you can reconnect that wire and then try to start the engine. Of course, it's kind of a negative test... If it doesn't start, you know priming didn't help. But if it DOES start, you won't know for sure if it would have started even if you DIDN'T purge. But it's an easy way to mess around with it anyway.

Jim, Thanks for digging into the Millington thing. Did you happen to ask the ZCON Facebook folks if there was a shuttle available to the people's choice show? (I'm guessing since you have your car there it wasn't at the top of your mind...) I agree about the venue and the timing. Twelve unfamiliar miles away and the timing is tight. I hope the hotel's water system can handle just about every room taking a shower at 5:00 on Saturday eve. If you do want to take your car to the people's choice portion of the show (and I sure would if I were you), I'd be happy to give you a hand loading your car before the banquet. Bug out of the show a little early and maybe another pair of hands will be enough to allow you to go and still get loaded in time for the banquet? And I take the blame for the derailment. I kinda turned the thread into "all things ZCON 2015".

Yeah, I was considering staying off-site as well to save $$, but went with the Hilton. I think there are a couple other hotels in the immediate area... Would you like me to poke around online and see what I can come up with?