Captain Obvious

Yeah, that's just an unacceptable situation. Sounds like it was intermittent, and without figuring out definitively what the problem was (is), then you'll never trust it. That's where I was with my previous helmet, although I believe I can identify the issue as shadowing the (one and only) arc sensor. So is there a number on the internal battery? Can you tell if it's Ni-Cd, or Lithium? Reason I ask is that if it's Ni-Cd, then it might be rechargeable by the solar cell. But if its lithium, then it is not rechargeable.

I wouldn't be surprised if the dealers just pulled them off and replaced them with round tops as well. Sure would have saved a lot of time for their techs rather than having to understand and properly set-up the flat tops. I wonder. Anyone here have any dealer experience from back when these cars were still going to the dealers for service? What was the internal Nissan reputation of the flat tops?

My understanding is the solar does not charge the batteries, but acts as an "alternative" power source. In fact, I don't think lithium button cells are rechargeable at all. I think the screen will operate from whichever power source is higher, either solar or battery. I think the marketing descriptions usually say something like the solar cells "extend battery life". And they do that "extension" by providing an alternative power source. And the more you draw from the "alternate", the less you have to draw from the battery. So how is it that you made your original determination the helmet had failed? Did you draw a welding arc and it did not go dark? Or did it just stop going dark when you looked at the shop lights?

Nice work. Soon people will be clamoring all over each other to replace their round tops with flat tops. OK, maybe not. Do you really think that one diaphragm was folded over and pinched? I would expect a permanent hard crease if that were the case. Maybe it just shrank up a little and rolled under itself after you took the power valve apart. Doesn't really matter though as you're replacing both of them. And I think I mentioned before... Don't throw out your old bowl seals. You may find they work better than the new ones from the rebuild kits.

Well if the volts go all the way to the left, then there's a problem with the fusible links, or (hopefully not) something more serious going on with the wiring as Wayne mentioned. For the meantime though, I want to believe that the wiring inside the harness is OK at this point. So the last thing you said "red closest to the windshield" leaves me a little puzzled and makes it necessary to drop back again and do some verification about the link positions. Here's a pic I whipped up showing the correct fusible link positions and their basic functions. This pic is from my 1977 car and I have personally verified that it is correct for 77: I have indicated with the title of the pic that it applies to both 1977 and 78, but full disclosure... Even though I believe they are the same, I have never personally verified that 78 is the same as 77. So first thing to do would be to verify that your links are the same as mine and here's an easy way. One of the links goes to the headlights and nothing else. Nothing. Turn your headlights on and (after verifying that they are on) disconnect the link I have labeled "headlights". If the headlights go out, your 78 is the same as my 77. If the headlights don't go out then 77 and 78 are different.

Excellent. One other thing to double check... I've seen situations where the shank on the aftermarket lug nuts is a little too long and will actually bottom out on the rotor or drum face before the wheel is clamped tight. The problem occurs when the shank is longer than the wheel flange is thick. Yours are probably fine, but you should check that if you haven't already.

Well I'm not yet ready to condemn the ignition relay. That blinker test was just a quick and dirty way to do a rough test. If the blinkers DID work, then you can be pretty sure that the relay is working. But if the blinkers did NOT work, then there's a number of things that could cause that, including (but not limited to) a bad ignition relay. In fact, the same (largest) black fusible link that would cause the voltmeter to read zero (or four) would also cause the blinkers to not work as well. (It would also cause the dome light, map light, brake lights, horn, etc. to all fail.) So, which fusible link was it that you found to be bad? What color was it and what position on the car? And you never answered... When the problem is occurring, does the volt gauge read all the way to the left (like 4V)?

And for anyone getting ready to print out a big copy of revision "M" to hang on their garage wall.... Don't do that right now. There have been some recently discovered issues in Rev "M" and I believe there will be a Revision "N" coming out soon to fix those issues. So if you can hold off for a little bit, do so!

Looks good! So I'm assuming after you filed off the burrs of extruded metal in the lug holes, the lug nut search got a lot easier? Everything made sense?

Arrrrrr!!!

Well let me back up just a little bit and clarify something... You said in your list of symptoms the following: So the statement that I want to clarify is about the voltage gauge.... So what you're saying is that when the problem is occurring, the needle on the voltage gauge is swung all the way to the left at like 4 volts? Like the battery is not connected at all. Is that correct? If so, then there is most likely a problem with an intermittent connection with the black (largest) fusible link. As for checking the ignition relay... There are two sections to it. One section sends power to a bunch of fuses when the key is turned to the ACC position, and the other section sends power to a bunch of fuses when the key is turned to the next click in the ON position. The click you're hearing when you turn the key to ACC is the first side of the ignition relay, and based on the fact that your heater fan, defroster, and antenna work, that side is working correctly. The other side of the ignition relay (the side that is engaged with the key in the ON position) powers (among other things), the turn signals. So with the key in the ON position, the turn signals should work. Check for that next time the problem occurs and let us know what you find? The above is a non-meter required way to check the function of the ignition relay. If, however you have a meter and want to test the relay a little more directly... Measure the voltages on the fuses, You should see the bottom three on the forward column (closest to the firewall) go hot when the key is turned to ACC. Those three, I believe are labeled AIR CON, WIPER, and RADIO. Then on the next click to ON, you should see the two above that go hot. I believe they are labeled FLASHER and FUEL GAUGE.

No kidding. I think I tore a rotator cuff just looking at that pic.

Sounds like a fusible link issue to me. Pop the hood now and remove the plastic covers off the fusible links. Don't wait until the problem occurs. Remove the covers now. Then the next time the problem does happen, pop the hood again and wiggle the fusible links around and see what happens? Start with the thickest one (probably black in color). The reason for removing the covers now is because sometimes they are a little difficult to get off and you don't want to knock the fusible links by accident. You want to be able to isolate what wiggling (if any) has an effect. And if you bump a fusible link while removing a cover, you won't be able to isolate the issue. Of course, if you pop the covers and everything under there is loose or green or bubbly and burned smelling... Then you might just assume that's where the issue is and start working on it without definitive identification.

My shoulders would so love something like that. Looks great!

I took a quick look at Lincoln's website and the docs say the battery in the 1840 is replicable. I'm guessing that's only for the new ones and yours is old enough that's not the case?

We aren't expected to get a lot out of this coming storm in my neck of the woods. I'm at the warmer end of the state and last time I checked, most of it is supposed to be rain. North central portions of PA though up through New England.... Look out! The more uncomfortable part (for me anyway) is coming end of NEXT week. It's gonna be very cold for an extended portion of time. Check your antifreeze and put another log on the heat pump.

Exactly. I'm fully confident in your confidence!

From what I've seen, the 260 is plastic and is the same as the 280. I have no idea about the history of the 240 blower I have. That plastic impeller on it may or may not be the original one as I have no insight into the history of the blower. But the motor itself (which still has a 240 part number on it) is definitely from a 240. Sounds like I have the valuable rare late model 240 blower assy with the lighter plastic impeller? An alternative to changing over to the Honda blower to get away from the heavy air robbing metal impeller? LOL. Open to offers!

Yeah, the chemistry isn't anywhere near my field of expertise either. But I do know that hydrofluoric acid is really nasty stuff due to it's affinity for calcium of which you have a bunch inside your bag of water. Here's two garage rules... Don't burn any of the fluorocarbons due to the risk of creating hydrofluoric acid. Don't electric weld anywhere around chlorinated carb cleaners due to the risk of creating phosgene. You, being in CA, probably can't get your hands on any chlorinated cleaners anymore. https://www.youtube.com/watch?v=paH97dYR6Lg

I wonder when they changed over to plastic impellers. I wouldn't consider a 72 to be an "early" 240. Makes me wonder what year the plastic blower assy I have came from. I know it's a 240 style assembly, so it has to be 73 or earlier. Maybe they changed over in 73? Or maybe someone in the past years had replaced the (original metal?) impeller with a newer (plastic?) one. In any event, it's just a curiosity. The 240 blower assy I have is just sitting on the parts stack.

Haha!!! Exactly! That's the one! I was just leaving the (subjective) "ugly" portion out of it and was letting that part up to the interpreter.

I've got a 240 blower (of unknown year) and a 77 280 blower here, and both of them have a plastic squirrel cage. I'm guessing the early 240's used a metal cage?

Well there's your problem... Maybe try loosening them instead of unloosening them? Seriously though, good luck with the endeavor. My only word of advice is of potential personal safety... The active ingredient in that freeze spray stuff (R152) is difluoroethane, and I'm no expert on the topic, but one of the components of flame decomposition of many of the fluorocarbons is hydrogen fluoride gas. Problem with hydrogen fluoride gas is that it turns into hydrofluoric acid when it comes into contact with water. And as a fictional silicon life form once pointed out, you're a bag of mostly water. Short story? I'm certainly no expert in the field, but I don't think it would be a good idea to work with a torch in one hand and the freeze spray can in the other and don't light the freeze spray on fire. Speaking of such things, I did exactly that with a can of R134 (tetrafluoroethane) a coupe months ago. And 24 hours later, based on the corrosion spray pattern behind what I was working on, I think I created some hydrofluoric. I had all the ingredients there at the same time. Very very nasty stuff.

Or Death Stars?

Is it just me, or does anyone else see disco balls when they see this pic?