New World Datsuns...

Fires freak me out. Mostly because I have almost no sense of smell so by the time I actually smell smoke, it's too late. Glad it wasn't too serious. Good thing you've got stacks of spares.

I could barely smell it, but smoke coming out from around the edges of the cluster(as it had no trim cover yet), and the defroster edges was the obvious sign, and it kept coming out after I turned the power off, it completely melted the plastic bulb holder, it was just one big blob of melted plastic.
The worst part was that it also melted/destroyed the whole circuit board around the power supply to the gauge regulator, it didn't melt any of the circuits, but where the tang stuck up/was held in place with a rivet was now a big hole, the tang was not connected to anything anymore.
I am thinking about installing the 1980 720 wiring harness, but I am not looking forward to doing that even though I have done it several times, if I am going to do it I really need to have everything ready as when I do it I will also be converting over to LED taillights which I don't have yet.

I started putting the 1980 Datsun 720 wiring harness in today, one has to literally take the complete dash out and even take the heater box out or like I did disconnect it from the firewall without removing the hoses move it around till one can get the wiring lume behind it.
I got the 521 harness out and the 720 harness routed, tomorrow I will try to get the engine compartment done except for the headlight pigtails, then I will work on getting the dash back in.
I didn't disconnect the battery when I should have and burnt the wiper motor ground wire, I expect I will never do that again, I think I can save the wire, but need to cut back the covering to see how far it is burnt towards the motor, it looks good at the motor itself, but that don't mean much.
This isn't really just a wiring harness swap, I have to combine/integrate the 720 harness into the 521 components, it can be done, but it takes time.

I'm not jealous.

I just spent most the day trying to get the 4 ways and turn signals to work, I just do not understand what is going on.
First I tried to get the front park lights to work, first I used 720 turn signal assemblies and it was a fight, at first I could not get them too stay on at all, some would flash every once in a while while I was wiggling them, so I would unplug them and use a test light, sometimes I had power at the plug, sometimes I didn't, if I twisted on the connection really hard sometimes they would come on, so I gave up and wired them to my 521 park lights, they came on and stayed on using them, I then wired the turn signals to the 521 buckets also, I spent hours getting nowhere, I finally took all my flasher units I have and tested them in the 520 as it has the same harness, they all worked fine, none of them did anything in this truck at first, at first i was just trying to get either front light to come on let alone getting it to flash, after hours of screwing around right around dark I finally got the damned 4 ways to flash a couple times with the only flasher that appears to work in this truck with a 1980 wiring harness.
Oh I forgot I did get the headlights to work, but all 4 come on and appear to stay on even though they are not in the brights position, I tried 2 different turn signal assemblies and 2 different 4 way switches with zero forward progress.
At the end of the day after it got dark I found a way to make the right and left turn signals to work using the 4 way flasher and a jumper wire, then all of a sudden the 4 ways started working, I gave up and packed up and came inside, not sure what to do now, I never got the turn signal switch assembly to light anything up except the park lights.

Well I figured out the issues with the 4 ways and turn signals, it was 2 different things, I took the 4 way switch apart and cleaned it, it was dirty in there, but the second issue was the biggie, remember I said I tried another switch assembly, well it was the switch assembly I have been trying to use, but between the 2 different issues I could not tell what was bad, I also took the turn switch assembly apart, cleaned it and then tried to put it back together, I tried and tried and it would not seat properly, so I got to looking and realized that I had likely had assembled this from different switch assemblies and then tried using this before and I could not get it to work so I threw it in the box for parts, well it had to do with the horn wire, I ground off a little where it was too fat to settle in its slot and it went back together, I installed it and everything works now.
I likely got impatient last time and gave up, I cannot give up this time as I really don't have another switch assembly made for this tilt column, the other one I tried was for a non-tilt column, all the wires plugged in, it just would not fit on the column, it likely didn't work yesterday because the 4 way switch was dirty and so was this assembly.
I started it and ran it for a minute or two to make sure it ran after wiring the fuel pump and the tach, I also have power to the rear plug for the taillights, I used my test light to check, when it quits raining I will likely go out and start wiring the instrument cluster.

The instrument cluster is basically wired although I am going to start looking for plastic bulb holders that will fit into the holes for the dash lights and bright indicator light, I powered the dash lights for now on a keyed circuit, key on, dash lights on, but I would like to be able to adjust the brightness, if I can figure that out I will likely do it to all my trucks.
I went to where I thought a Radio Shack was but they are not there anymore, I just searched them and I have one in Vancouver within 5 miles, I will go there tomorrow and see if they have what I need.
Can LED lights be adjusted?
Tomorrow I will finish up the instrument cluster and then wire in the taillights, if I have time I will look into the headlights.

I didn't know there were any Radio Shacks left.

I finished this up today, I only have one issue, when I turned the headlights on all 4 come on and stay on, not sure why yet, I tried different relays without any change, so I pulled the relay out and made a jumper to turn just the low beams on, this will do for now, after I got the headlights put back together I began to wonder if I plugged the high beam bulbs in upside down and if this could be the issue, it doesn't seem like it would make a difference but who knows, I just didn't want to remove right now as I was cleaning up and am tired, I will deal with it tomorrow or Sunday.
I finished the cluster, the rear taillights, headlights, and the wiper motor wiring, I also got the air horns working which I didn't really understand at first, I could not get the 521 relay to work, what the problem was is that the 720 wiring harness has a relay already and I was putting the 521 relay in after it, to me I think it should have worked anyway, but once I removed the 521 relay the air horn started working, although I don't think it is getting enough power thru the stock 720 relay as it sounds pathetic, I don't use it much so I am not going to worry about it right now.
This truck is now back to being the work truck.

Mission accomplished.

I can hardly believe how bright the dash lights are(all of them), in the past it was hard to see any of them except for the charge/oil lights, now even they are brighter, that 521 wiring harness and all the modifications I made to it over the years took its toll, even the lights in the console work now, I should have done this years ago.
By the way, my engine would not shut down after removing all the fuses in my 521 fuse block, now it does shut down as I tested it by pulling all the fuses in the 720 fuse block one at a time while it was running.

I spent an hour trying to figure out why the brights are always on when the headlights are on without results, but I just now realized that when testing the relay circuit something is happening that I don't think is supposed to be happening.
It has 5 spades on the relay, the 2 top center ones say NO of which the lower one connects to nothing, the one next to the 2 spades say COM, and the 2 lower spades say COIL, if I connect the NO(only hot one) to one of the COIL the outside headlights go on and they appear to be in the bright mode, if I connect that hot NO to the other COIL it blows the fuse every time.
I just pulled the fuse block off the kick panel and looked at the wires, even though the 2 lower ones both say COIL one is the ground, the one that blows the fuse, I am not really understanding this, unfortunately I only have a 1982 720 diesel wiring harness diagram to look at, I do not have an 80 gasser diagram, but the headlight circuit should basically be the same.
I will look at it more tomorrow.

Nissan headlight wiring always seemed overcompicated to me.

Well I got it figured out, I should have known when the turn signals didn't work properly and I had to fix the combination switch, then when the lights didn't work right either that it had to be the combination switch also.
I tore it all down and installed the square headlights, it didn't work properly, then I used the other combination switch and it worked properly, I have no idea why this extra combination switch didn't work properly the last time I tried it, so I took it out, set them on the hood of the 720 and compared them, it turned out that when one twists the lever to turn on the headlights the other one had a bump that this switch didn't have, so I took the lever off the extra and put it on the one I need to use and the lights work properly now with the round headlights, but the freaking brights indicator would not work, so I added 2 wires to the relay wiring, checked to make sure everything was still working properly and it was so I buttoned the thing up and called it good.
It likely took me 3 hours just to get the brights indicator working, everything it a fight with this wiring.

I tried to fill it up today to see what the fuel gauge showed when full but it took all the money I gave the gal($40.00), but when I turned the key on it went almost to completely full, so it appears to be working properly now with this wiring harness.
Again I will say the brakes work better than they ever have, this truck will stop like I am not even hauling a trailer now, the trailer does have electric brakes though.
I don't like the power steering as much now, I have to steer it full time as it doesn't center itself anymore like it used to.

So I believe I have figured out why I could not get the brights indicator light to work, there are 2 red/green wires in the 720 dash harness, I believe I grabbed the wrong red/green wire, I am not sure if I am going to fix it or not as I made my own wires for that light.
If I go in to change the dash lights if I find something that will fit in the 4 holes I may fix that also.
I should have looked closer as I only recall seeing one wire with them colors.

I have been trying to figure out how I was going to have dash lights that were adjustable, I have been unable to find any 2 wire plastic bulb holders that are the proper size, well I think I figured it out, what I did was rip the positive side connection out of the stock bulb holder, then I drilled a hole in the center of the bulb holder, then I found some old lights I was not going to use and I pilled the wires out of the housings so I had the ends I needed, I then found 2 clicker pens with them little springs inside them and cut the little springs in half, I put the half spring on the wire, then I put the wire with the spring in the bulb holder, then I put the light bulb in and tested to see if it would work, it worked great, I wired the 4 bulbs into the instrument cluster I robbed the bulb holders from and it appears to work fine, I will use the cluster circuit board as the positive side and the wires as the negative side, this should make the dash lights adjustable once I connect them to the proper wires.

Crafty

I installed the dash light harness I made today, am waiting till dark to see how bright the dash lights are and how well the dimmer switch/knob works.
I also looked at the wires I have for the brights indicator light, I tried the only R/G and R/B wires there are in that dash harness, so I have no idea why I could not get the brights indicator light to work, so I left what I made in place.
I didn't put a light in the dash cluster to indicate when the e-brake is on like I did in the 521 kingcab, maybe someday I will do that.

Is it dark yet?