Captain Obvious

So all this talk about electrical problems and wiring diagrams and switch rebuilding... The problem was the check valve between the manifold and the vacuum bottle?? That's awesome!! Glad it was that easy!! (And cheap!) Awesome! I can picture you in your car in the garage tonight, moving your lever back and forth. Back and forth. Back and forth. Go ahead...

Oh, and all this talk about the magnet valves and vacuum tubing makes me sooooooooo, soooooooo glad that I changed over to the electric servo control for the HVAC system! So glad!

I know, right? And just because I can post pictures WITHOUT photosuckit, here are some pics of the fan control switch. Might not even be the problem, but just because I can. Fan switch: Unbend the tabs to open up the switch. Green crusty grease and corroded copper contacts inside. The four nibs along the top are the four fan speeds. The solid bar (the OFF bar) at the bottom is the "switch is NOT in the OFF position". (for my nerd friends... Get it? "OFF bar"). Anyway: Cleaned up all the contacts with some scotch-brite or 800 grit sandpaper. I put some grease on after the pic: Rebend the tabs back over to hold the switch back together and you're done. What was intermittent, now works perfect:

Who's got the bigger garage? That's friends with benefits! Is that like "Send picture of boat and trailer?"

The magnet valves are just an electrically opened valve. With no power on them, they are closed, and with 12V on them, they should open. You should not be able to blow air through them with no power to them, and if you put power on them (and they click), you should be able to blow through them. Other thoughts? The magnet valve on the left (in the wiring diagram) only actuates when the compressor runs and it supplies vacuum to the FICD. So that one will never actuate if the wires are broken to the pressure switch. But that one has no effect on anything other than the FICD, so it shouldn't be affecting heat at all. The magnet valve on the right is the one that controls everything else, and it should be opening any time the key is in ACC or ON, and the fan is running. I'm not sure why they bothered to tie it into the ignition though. I'm guessing they didn't want you to drain all the vacuum out of the reservoir bottle while you were sitting with the engine off. Playing with the mode lever... Moving it around a bunch of times just to listen to the flapper doors move, until you had drained the vacuum bottle? Anyway, with that theory in mind, they cut off the vacuum to the system when the ignition is off. So, to test the rest of the heater system, you could completely bypass that magnet valve. Just jumper the vacuum tubing around it to test the rest of the system. You will be putting vacuum on the rest of the system all the time so you will probably drain your vacuum bottle overnight. But to test the heater, it should be fine. As a side note that might not really matter right now, but... There are two sections to the fan switch. One section is the 1 through 4 speed controls, and the other is an "fan is running" output. That "fan is running" output gets tied to ground whenever the lever is set to anything other than OFF and the "fan is running". The insides of my fan switch were green, crusty, and intermittent, and I'm wondering if maybe yours is as well. I took mine apart and cleaned it all up nice and put it back together. Works great now. I got pics if you're interested.

It's "Fronkenschteen". One piece at a time, my friend. One piece at a time!

Well if the underside looks as good as the top, you've got a real nice one there. I'm having trouble finding significant flaws or anomalies. GLWS! On a related note... So that's what the steering wheel is supposed to look like? Before they turned to cottage cheese?

Wow. That's very nice. It's not a one owner. It's a two owner, and soon to be a three owner. Regardless, that might be the best time capsule Z I've seen! Any idea why the original owner parked it in 1991? What's the underside look like?

I did my relay upgrade a little differently. I had the whole engine bay wiring harness out of the car and unwrapped apart on the bench. I rewired it to include relays for the headlights and the starter solenoid and then rewrapped it. And while I was in there, I also changed it to use the internally regulated alternator. It was definitely NOT plug-n-play. Mine was unwrap/cut/splice/crimp/wrap and play. I had a thread with a whole bunch of pics, but then photobucket turned sour and that thread is mostly useless.

I don't have any first hand experience with spacing the thin Autopal housings, but of the suggested solutions you mentioned, I think I would try the sticky foam tape first. Failing that, maybe some latex or silicone tubing? I think I would like them better than traditional vacuum tubing because they are softer?

Not saying the valves are OK, but just because the vacuum isn't getting through them, doesn't necessarily mean the valve itself is the problem. There are lots of other electrical things that could go wrong that would make the valves not operate when they are supposed to. Hoping I'm not telling you stuff you already knew, I whipped up this little snippet from the wiring diagram:

I'm positive there was no metal to metal contact originally. That's the whole point of the rubber isolation. I think this is a really cool idea, and whether it succeeds or not, I love seeing the internal workings of something that was never intended to ever come apart. I suspect the largest stumbling block to this project will be finding something that will stick to the metal as well as the original rubber did. I've got no experience in that field and have no input other than asking if you have considered using a rubber like the original? There are lots of people molding and vulcanizing rubber. The processing doesn't look that difficult if you can find suitable raw materials.

I noticed a huge difference in the brightness (whiteness) of my old original sealed beams after doing the headlight relay upgrade. I don't know what my car looks like coming at me in traffic with the headlights on, but it's gotta be a lot whiter and a lot less yellow than it used to be now that the filaments are getting more current. Before the upgrade, I was getting less than 10 Volts at the filaments. I think I was getting eight something on high beams. Now that I've done the upgrade, I'm getting darn near full battery voltage. No surprise, but it really makes a difference! Oh, and sorta related... I took a look back through my notes and had this in there about the Autopal H4 housings: Some people say they aren't thick enough and will rattle around if not padded with a spacer - A1L-11-04-2011 So I don't know if you found that to be the case, but I've heard others have had slight issues with fitment.

Hahaha!! Exactly. I had forgotten about that one. Thanks!

Haha! It's a dimmer. No it's a paperweight! So my input on dimming dash LED's is that you may get a small amount of dimming function with the stock system if you just replace the bulbs with LED equivalents. But if you want a wide range of dimming (including full dark), you'll need to change over to a pulse width dimming system.

What about the Miami and east FL coast guys? Anyone heard from any of them?

If there's really a chunk of gasket got pushed out, that would be curious. If you do find that to be the case, before you pull the head maybe I'd take a look and make sure your valves are adjusted properly? Thinking that maybe if your exhaust valve isn't opening (or opening enough?) you might be building up more cylinder pressure than normal?

Glad to hear that some of you folks are now on the far side of that thing and came through OK. I hope the folks down further in south Florida are OK. From what I hear, it's going to be no picnic even all the way up into GA TN, and AL.

I've got throttle body binding as well, and that's what started all of this. I originally masked the problem by giving my throttle return spring on the butterfly shaft an additional turn. Didn't like the way it made the throttle feel, so next I spent a completely unreasonable amount of time adding Delrin bushings to my throttle body. That seemed like it worked at first. Then I discovered that it's great until the engine heat soaks after a ten minute stop. And then it's even worse than what I started with. So now I've changed over to a completely different throttle body from a different car. Includes ball bearings and vacuum seals on the shaft. Currently the repurposed throttle body (with it's cobbled together temporary installation) works great , but it would work even better with a cable actuation since that's what it was originally designed to use. I will take some pics and post some non-nebulous details as soon as the system isn't embarrassing.

Glad you got things working! Just make double sure you have the terminals in the correct locations. The common is easy to find, and depending on how good your Ohmmeter is, you might be able to identify the HI and LO filament connections as well. I did have this drawing in my files. Might help explain some of the issue Seems almost evil of them to have done this? About the fuses, if there is only one fuse, I'd use 20A (instead of the 30 the harness came with). If you somehow get the harness manufacturer to give you something with two fuses, then I'd use a pair of 10's (just like the original Datsun configuration). And as for the different harness upgrade options... The other already available plug-n-play harness options for the earlier years are much simpler to install since you don't need to have access inside the headlight buckets. So there's the tradeoff. For the 240 and 260, the other harness is plug and play without taking the bulbs out. Makes it easier. You, with the 280, don't have that as an option. Compound that with the fact that you were already planning to replace the headlights with something newer and were going to have the bulbs out of the buckets. Wasn't going to be any additional work for you. Different strokes.

zKars and I were saying the same thing. He just said it with a Canadian accent, eh. Haha!!

Yes, you are still using the stock system, but here's the difference... From the factory, the stalk switch and all the original wiring sent power to the headlights. Now with the harness you just installed, the stalk and original wires send power to the relays instead, and the relays switch the power to the bulbs themselves. So the trick is that the relays only draw like maybe half an Amp total, while the headlights will pull almost ten Amps. That reduction of current through the column switches and original wires relaxes the load on the old tired dirty system. Then where does the high current come from to actually run the bulbs? That's the new fused connection(s) that you tie right to the battery. With those new connections, the relays will pull current directly right from the battery, pass it through the bulbs, and then return to ground with the two new ground lug connections you made on the upgrade harness. The bottom line is that with that new upgrade harness, the relays do the heavy lifting, while the switches on the column just tell the relays what to do. Lets see. What else? I'd be surprised to learn that they moved the connections around between the old sealed beams and the H4 bulbs. I didn't look into it, but wanted to challenge you on that. They swapped hi and low beams? Not saying they didn't, but kinda surprised if they did. You sure about that? Yeah, I forgot about that fused cable jacket inside the bucket. They heat fused all that stuff together in an effort to seal the harness jacket against water coming in. Sounds like you handled it fine. When I went through this, I made the holes in the back of the buckets a little larger and used larger grommet seals. Just large enough to be able to pass the connector shell through the housing without having to take the contacts out again. About the fusing - You plugged the new harness into one of the original headlight bulb connectors. The fuse for that side (right) can be replaced with a 1A instead of the original 10A. And the fuse for the left side can be removed completely. Empty slot. And I'm a little unclear about the 30A fuse in the new harness. I'm thinking that maybe it's a dual fuse? Their drawing shows two fuses, and two wires? Can you take a pic of that part of the upgrade harness to make sure there's no confusion? I loved your little descriptive story. I understand completely! That's exactly how I feel when I approach anything to do with body work. I can deal with the electricals and mechanicals, but I'm in cold sweat mode when it comes to the body!

Yup. Plug it into either one and tape the other stock side up. Doesn't matter electrically which side, but you have already correctly identified the better choice of using the pass side (right) because it is closer to the battery. Good luck, and I'd replace the original 30A fuses with something smaller. I'd use 20A's for a final value, and I'd even use 10s or 7.5s until I was sure things were working properly. 30 is way bigger than you need there. Unicorn riding a rainbow unicycle chasing a Z logo in the sky! Haha!!

" I just need to know where (location wise) and what wires will allow me to connect the 3 wires from the generic harness" In short... The three wires to connect the generic harness exist at the three prong connector at the back or either headlight. Right there at the glass globe. Inside the headlight bucket. You can't see them without taking the fender liner out and removing the headlight bucket from the back side of the sugar scoop and then taking off the retaining ring that holds the headlight bulb in place. OK, so not so short?

What's that? Do I see a Z logo in the sky?? Haha!! I don't have a lot of time right at this instant, but I'll try to add some quick value where I can. First, for reading the wiring diagram... The "O" means "makes a connection", and the line between "O's" shows you where that connection is made. So for example with regards to the headlights... If you look down the OFF column, there are no "O's" because there are no connections. Then when you rotate the switch to the 1 position, there are "O's" in row's 4 and 5 which are connected by a line. This means that "In position 1, wire 4 gets connected to wire 5". Progressing to position 2, "Wire 4 is still connected to wire 5, and in addition to that, wire 6 gets connected to wire 7." In English: "When in position 1, your parking lights are on, and when in position 2, your parking lights AND your headlights are on". That's how that diagram works. Second, that harness (with some caveats) is truly plug and play. It does not attach to anything under the dash, nor does it plug into any proprietary or unusual connector used just on the 280's. It makes connection to the three prong connector right on the back of the headlight. The intention is that you pull the three prong plug right off the back of the light and connect in that harness instead. Now for the caveats... First caveat, as you discovered, is that the length of wires between the two headlights need to be long enough to reach from one bucket to the other. If this thing was designed for a go-cart, that may not be the case. The second caveat is that you need to be able to actually physically get the wires into place, and here's where the Z's are a little difficult because of the way the headlights are physically mounted in the buckets. Problem as zKars alluded to is that the hole in the back of the headlight buckets isn't large enough to pass any of the connectors through. Your choices are to make the hole in the back of the buckets larger, or to take the contacts out of the plastic connector shells and pass them through the bucket and then snap them back into the connector shells. Not too difficult, and if I was going to use this type of harness, that's probably what I would do. Hope some of that helps, and if not, I'll mess things up even more when I get more time!