Captain Obvious

Haha! Yes, Zed Head. It is possible for me to lock the keys in my 77. And I suspect that even as methodical as I am, I will eventually do that someday. Greg, Yup, my 77 came to me with multiple keys as well. One or more of the previous owner's had issues with the locks and had replaced some stuff. I had a different key for EACH door, and a third for the ignition, glove box, and hatch. One of my past projects was to rekey everything back to one key. Hopefully what I've got in there now will last the lifetime (of my ownership) of the car. I don't know when they made the change to one key, but since it's in the 77 Owner's Manual and Zed Head says that his 76 also uses just one key, I don't think there were any 77's that used up old stock. Nobody could really know for sure, but I suspect your car had some work done. Don't lock your key(s) in your car!

Greg, If your 77 works that way, your car probably had the doors and ignition locks replaced at some point. According to the Owner's Manual, your car left the factory with the same key working everything.

Zed Head And just for lock trivia... The 77 and 78 doors can be locked with or without the key. If you push the lock button down before you close the door, you can hold the door handle up while you close the door and it stays locked. If you just close it without holding the handle up, it unlocks itself when it latches. Page 6 of the 77 Owner's Manual describes the single key for everything and the locking procedures. From what you said above, it sounds like this feature started in 77? Yet another reason I love my 77!!

Earlier years used multiple keys, but the later years did not. The later years, like yours, used one key for everything. However, many of the lock components have worn out and have been replaced over the past forty years and there's no guarantee that what you have in your car is original or not. Also keep in mind that the door locks and ignition switch are generally used much more often than the glove box and hatch locks, and hence, usually wear out first. It's conceivable that your car had the doors and ignition lock replaced at some point and that's the key you have in your possession. And there's no guarantee that if something was replaced (like the doors and ignition locks) that they keyed them the same as the car used to be. Probably should have, but no guarantee. All that said... If you're just trying to get into the glove box, you can take the three or four Phillips head screws out of the hinge on the bottom of the glove box door (above the passengers shins) and get the door open a bunch. And once you have it open that far, you might be able to see what's going on with your lock and latch that is making it not open the correct way.

Yup! That's the one! Somewhere near the top is "Today". And somewhere near the bottom is "New owner discovers horn doesn't work and complains about previous owner's shoddy workmanship."

jwtaylor, Yes, a brass screw would be a better choice, but steel is what I had handy at the time. I made sure there was significant meat on the contact above the screw tip though, so I'm not really worried. I'm guessing I should be able to get at least twenty to thirty years out of the contact before I need to check it. I'll put a note in my follow-up folder.

So you've clearly got the welding part down and have used it on busted bolts and the like in the past. Only problem is you didn't know what you were dealing with. Now we both know. And I thank you for the info in case I ever find myself in a similar situation. It's always easier to take the SECOND one apart! My mentors referred to that as the "Brute Force and Ignorance" (BFI) method and I'm quite familiar with that method as well. So one more detail about this stuff... You really only need to get ONE ball out the hard way. Because once you have one side out, you can press the other side out by pushing the pivot pin through the housing. So the job is really only 50% as hard as you might think, right? Haha!! That happens when you get older, right?

Haha! My pleasure. Just remember that I gave a "non-answer" though!! Just anecdote and input from someone not trained in the fuse art. Wish I knew more and could have been more definitive. Still awaiting SteveJ's wading into the fray. Maybe he's got the kung-fu.

My thoughts? I honestly don't know. My questions are: "Is there any functional difference in operation between fuses and fusible links?" and the follow-up question of "When designing in a protection device, what would make you choose a fusible link over a fuse?" I spent a little time looking into the above questions a while ago and about the only thing I could turn up on-line was that fusible links were historically used in applications where fuses were unavailable because of the current capacity. So back in the mid seventies, forty and fifty amp fuses, especially in the glass tube style used in our fuse blocks simply weren't available. But if you look under the hood of cars now, you see cartridge fuses of 100A or even more coming right off the battery terminal. I guess the answer could be that parts like that just simply weren't available back when our cars were designed, and if they were designing them again today, everything would have been fuses instead of of fusible links. However... In engineering, frequently even the seemingly mundane is often much more complicated than it appears to the non-expert. I wouldn't be surprised if an EE from Bussman would be rolling his eyes right now at my lack of understanding.

Careless, I wasn't proposing to push the balls through. I know that won't work because of the step in the id (it's known as a counterbore). I was just musing some ways to PULL the balls out because, by design, pushing them through simply cannot succeed. The suggestion of heat would make it easier to pull the balls OUT if you could get a grip on them. I mean... Yes, there's a slim to zero chance that heating the housing and then rapping it on a hard surface might knock the ball out of the hole in which it's pressed into, but very slim chance. Sure, I'd try it, but I would be more surprised if it would work than if it would fail. And as far as if the balls are hardened or not, just because they didn't deform isn't really a true indication. Again... slim chances that they are NOT hardened, but anything is possible. If the balls are hardened, you might be able to drill through them with a carbide bit, but it's not as easy as it sounds. Other ideas? If I had two pumps, I'm confident I could salvage the arm from one of them and the body casting from another. Then I could put one pump back together using a different (removable) means to hold the arm in place and seal the holes. You might be able to weld a stub to the ball and use the stub to pull the ball out. The heat from welding might also temper the balls to make drilling easier. Temper the balls. Just felt the need to say that again...

Excellent. And I believe your understanding of the way the system works and the wiring involved is spot on. If you wire things up as shown in that manual sheet and take the override circuit green wire hot, the fan will run regardless of key position or sensor temperature. Only other input I would have about the override switch thingie is that they show a 15A fuse in diagram #4 and I believe that is severe overkill. I'd be surprised if a 2A fuse wasn't big enough. I don't know exactly how much current the relay primary coil draws, but I guarantee that 15A is way larger than required there.

And this talk about fans reminds me.... If you're looking for something under the dash instead of the engine compartment, there are two curious signals up above the fuseblock that show up on the upper middlish of the wiring diagram labeled as "To Cooling Fan Motor Sub-Harness". One of those wires is hot at all times and the other is hot in ON and START. You could use one or both of them to connect to your module, especially if you're locating it in the glove compartment. There was some discussion about these wires in the past in this thread: http://www.classiczcars.com/topic/46256-always-hot-connection-for-radio-install/

Gotcha. So you're looking for a low current source that goes hot when in ON. There's lots of ways to do that, but one of the simplest would be to tap into the white/black that goes to your ignition module and your ignition coil. That wire goes hot in ON and START

Bummer. If the Nikki pumps used balls pressed into counterbored holes on both sides, that's a tough one... Are the balls hardened? If not, one could drill (and maybe tap) them to extract them. I give it pretty good odds that they ARE hardened, but you never know. Some heat might also help with the removal as the aluminum case would expand more than the steel ball. Basically it's clear that they never intended those sealing balls to come out.

I'm not exactly sure what you would be using the 12V ignition signal for. Are you planning to use this connection as a high current source to actually power the fans? Because if so, then my answer is.. "There isn't one. Connect right to the battery and use a relay to switch the high current source." You would control the relay with a low current source that goes hot in ON and there are plenty of places to pick the up. On the other hand, if you're looking for that low current source that goes hot in ON to control a relay or a control module of some sort, there are several ways to do that. But I want to figure out if that's what you're looking for first.

Steve, Wow. You really went for a prepackaged fancy "module". I was picturing one of these more generic versions. Something that doesn't even have a case to facilitate ummm... curiosity http://www.amazon.com/gp/product/B00XE965RG?gwSec=1&redirect=true&ref_=s9_simh_gw_p60_d0_i3 So I guess if your module doesn't work out, you're out a whole two dollars and seventy cents. On edit - I like the uber generic description of that module I linked to! Do you think they could have gotten any more buzzwords in there?? DC Motor Speed Control Driver Board 3V-35V 5A PWM Controller Stepless DC 3V 6V 12V 24V 35V Variable Voltage Regulator Dimmer Governor Switching Build with LED Indicator and Switch Function"

Hahaha!!! Nice Janglish! I'd not noticed that before. Thanks for pointing that out. Reminds me of something I often see at my local Asian supermarket... They sell "Beef For Stir Fly". I've been tempted to bring it to their attention, but don't want to accidently risk an incident. Yeah, unless that four wire PWM does just tie the two positives together for ease of wiring, grafting that thing into the Z wiring would be a pain. You still need the green/white to go to the parking lights, but want to separate it from just the dimmed lights while leaving the un-dimmed ones alone. Let's hope it's just a tie point for ease of wiring.

One other thought... Maybe they're simply tying the positive out right to the positive in on the PCB... It might be a simple PWM to ground through a transistor and the only reason they included a separate terminal for positive out was to simplify the wiring for people who didn't want to put two wires under the same terminal screw? Without having one in hand to do a little reverse engineering I can't tell.

Hmmm... On those pre-canned four wire dimmers, it looks like they're actually DRIVING the output terminals instead of just pulling one of them to ground through a transistor. Two of the connections are easy: Negative in would connect to ground. Easiest place to pick this up would be the black wire at the dimmer connector. Negative out would connect to the low side of all the bulbs. Easiest place to pick this up would be the red/blue wire at the dimmer connector. But the other two connections are a little problematic... You would have to break the original connection between the combo switch and all the dimmable bulbs to insert the module between the two. Hate to suggest that you spend more $$ if you're already in the doghouse, but can't you just pick up a low side switching PWM controller like I used? Something that shares the same low side and just drags the bulbs to ground through a transistor? Would certainly be easier wiring! You'd make up the cost in time spent with your head underneath the dash! You want me to pick one up at the yard and send it to ya? My treat!

Steve, Haha!! Yes, I'll take the blame. I'm glad to shunt the heat since it's harder to feel the impact when I'm so far away. You're one of the people who are partially to blame for this anyway. Showing off your LEDs in Memphis and all. So, about the electronics... The PWM controller is typically a three wire device: First connection gets connected to a source that goes hot when the bulbs are on. Second connection is the interrupted PWM output which gets connected to the low side of all the bulbs you want to light. Third connection gets connected to ground. Problem is that the original pot is a two wire device, so you need to run a new third wire to the PWM controller. Or.... Through a little electronic Tomfoolery I modified the PWM controller circuit inside the box to make it a two wire device instead of a three wire device. I'll get into the details if anyone wants, but I basically traded a small bit of PWM adjustment at the upper end for the ability to eliminate the third rail. So instead of operating from (0% to 100%) mine now operates from (0% to ~98%). I don't miss that upper 2% of "full brightness" duty cycle. And in the unlikely event that you DO miss that upper 2% of brightness, you can switch to brighter bulbs or something. Only other trade off is that I'll need to keep one incandescent bulb somewhere in the system or bury a lowish value resistor in place of a bulb somewhere in the system. So you either need to add the third wire (which is also easy) or you can modify the controller to use two wires instead of three. I decided to modify the controller but either way would work.

SteveJ nailed the "why".... I'm messing around with LED lighting for the dash and the original resistance based pot style dimmer doesn't work properly. The original dimmer pot is 10 Ohms and has to be somewhat "matched" to the impedance of the original incandescent bulbs in order for it to work properly. When you go to LED's, the impedance is so radically different that the dimmer function doesn't work effectively anymore. Besides... It's cool? The PWM controller does contain electronics, but I doubt there's anything programmable in there. It's just a fixed frequency oscillator that they use to drive a variable pulse width output to a power transistor. You turn the knob and it varies the pulse width from 0% ON up to 100% ON. "You seem to be making a lot of brass extendo devices..." Haha! Because I can.

Most vehicles have long since changed away from a potentiometer based instrument dimmer to a Pulse Width Modulated (PWM) based electronic dimmer controller and I've been working on retrofitting one of these newer style electronic dimmer controllers into my 280Z. I poked around the junkyard looking for one that would mechanically fit in the original potentiometer location and settled on one from a late eighties to early nineties Toyota Camry. The main criteria needed are short stubby mounting depth and rotate control instead of a thumbwheel so I could mount it in the original dimmer pot location. This is the dimmer out of a 91 Toyota Camry: The biggest hurdle with this retrofit is that the shaft is too short, and because of that, this became mostly a mechanical project instead of an electrical one. I took the dimmer module apart and took the control potentiometer out: Mounted the pot in a "specially designed fixture" to be able to modify the shaft. I wanted to turn it down a little to fit inside an extendo-shaft. Here's the pot mounted in the fixture and the rough cut brass extendo-shaft at the bottom: I turned the pot nub down a little and bored the end of the extendo to fit onto the pot nub. After the rest of the machining is done I'll epoxy the extendo to the original pot nub: : Then for the other end of the extendo, I machined some splines to fit the original dimmer knob: Here's the completed dimmer next to the original dimmer pot. I glued the shaft together and everything looks great. I didn't mount it in the dash yet, but I did connect it up and it works great. I probably won't mount it in the dash until the off season. I'm going to pull my dash out for some HVAC work and it'll be a lot easier to swap the original pot out with the dash out of the car. Here's the completed dimmer:

I made the extendo contact. It's just a little piece of brass stock that I drilled and tapped for a small screw. Don't remember the size though. About the only dimension that matters is that its not so big that it hits other places you don't want it to hit. Not sure when I'll be in there again, but I'll measure it for you next time if you want. I think I'll have my dash out again this coming off season for some changes and if you haven't fixed yours by then, I'll have my wheel off then and can refresh my memory.

So after I did my steering wheel upgrade, I made sure my horn was working and it worked great. Then one day, I'm out driving around and making a turn and some guy pulls out in front of me. I hit my horn button and nothing. Doesn't work. Get home and test the horn again. Works fine sitting in my driveway... Turns out that my horn worked great AS LONG AS THE STEERING WHEEL WAS POINTED STRAIGHT AHEAD. But if the wheel was turned to one side or another, the slip ring contact lost contact and my horn didn't work. That took me a couple weeks and two near misses on the road to figure out. In the end, I made a little extendo contact and screwed it into place. Works great. Here's my original worn one and my replacement. The new one should last longer than I do.

If you're looking to get rid of the redundancy, you could get the upper warning lamps from a 75. Left side says "CATALYST" and right side says "FLOOR TEMP". That way you could fill all the available locations with unique indicators. I'm an idea guy. Never said they were good ideas though...