Posted May 28, 20222 yr comment_640957 I have decided that the wiring on my '73 is going to be complicated enough to warrant it's own build thread. I will post the high level stuff in the full-car build thread (https://www.classiczcars.com/forums/topic/51541-1973-rebuild/#comments), but the details and back and forth conversation will be here. This is going to be a huge learning process for me since I have no experience in this area. With that said, this is where I am with this so far… When I got the car, the harnesses were installed, but the car was otherwise stripped. I pulled the harnesses, gave them a cursory dusting off and stuffed them into a box. The dash harness is still on the dashboard, which is on a shelf. I have been tracking an inventory of modifications I want to make to my electrical system over the past few years as I work on the rest of the car. I had a lot of ambition when I first put this list together, but I have backed off from my initial list of additional components over time. This is what I am still thinking about doing: Anti-Theft Kit / Alarm (Mostly because I have one laying around that I never installed on my motorcycle) Auxiliary Fuse Box or an Upgraded Fuse Box Bluetooth Speaker Electric Radiator Fan, plus maybe a thermostat controlled switch that would allow it to run after to car is turned off. GPS Third Brake Light Under Dash / Footwell Lights USB Socket / Phone Charger LED Exterior Lights 100-Amp Alternator Radio Delete LED Headlights Rally / Fog Lights 12-volt Socket (Replaces Cigarette Lighter) Door / Step Lights (These are super rare and way too expensive) Other Considerations… Figure out where I am going to do this work (it's getting hot) Decide which type of wire for each component (TXL, SXL, GXL, etc.) Choose connectors (Original style?, Deutsch style?, AMP style?, Weatherpack style?) Decide which colors to use for each color in the original harnesses Find amperage / voltage / wattage for each component Determine ideal wire size for each component Choose distributor Choose fuse box, distribution block, relay upgrades Identify fuse and relay requirements for each component Draw up new / modified wiring diagram Choose wrapping material Find shrink-wrap labels for label maker Find retailers ___ Right now I have a pretty solid spreadsheet put together with all of the components I need, mapped to the wiring diagram, and tracking the parts I plan to buy. Oh, and I’ve never done automotive wiring before, so this will be an experience. Edited June 21, 20222 yr by Matthew Abate Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/ Share on other sites More sharing options...
May 28, 20222 yr comment_640960 Fuse size depends the gauge of the wire you're protecting. I recommend 10A for 14 AWG, 20A for 10 AWG or 12AWG and 7.5A for 16 AWG or 18 AWG. Don't forget about maxifuses or fusible links for the system as a whole. As I searched for vendors for wires with colored stripes, I found this place was probably about the most economical and flexible: https://www.sherco-auto.com/striped-tracer-wire.html You may be able to adapt this for fusible links: https://www.amazon.com/1J0937617D-Battery-Terminal-Volkswagen-Octavia/dp/B0863XLF6R As for current draw, let the factory fuse box be your guide to start. The fan is the highest draw, especially if you have AC. While the parking/tail light fuse is 20A, you can go to 10A and 14 AWG with LEDs. (IMHO the engineers undersized the wire in this circuit for incandescent bulbs.) The same goes for the flasher. The Common fuse is for the cigarette lighter. That can drop to 10A. I'm not positive about the draw on the wipers, but if you keep it at 20A, I would use 12 AWG instead of 14 AWG. The brake light circuit can also go to 10A with LEDs. Note: the fuse ratings I wrote are very much on the conservative side. However, I have seen enough melted fuse boxes and melted connectors that I prefer a conservative approach. As for wire sizes here is a rule of thumb. The wires for the large connectors should be 14 AWG. Use 16 AWG for the smaller connectors. On the 73 (and on through 76), Nissan started using the 9 pin connector on the headlight switch. That was a bad move. The connectors were undersized for the current of the parking lights, and that connector would melt down. For the large bullets, I would use 10 AWG. Consider trying 8 AWG for the circuits for the ammeter. Are you sticking with the ammeter or are you going to have a voltmeter instead? Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-640960 Share on other sites More sharing options...
June 5, 20222 yr Author comment_641281 Thanks @SteveJ! I think you already noticed this based on your comments, but I'll state it for anyone else who may comment: My overall goal in this is to make the ideal wiring system for the car with consideration to the modifications I am going to make, not to replicate the original. That said, I don't want to deviate wildly from original because I want to be able to go back and fix stuff if necessary. I also want to reduce complexity and weight wherever possible. However, I also think I will go heavier than necessary with the wiring so I never have to worry about that part of the system. The things on the ends of the wires are a lot easier to fix down the road than the wires themselves. ___ Here is my first pass at an inventory of components for this project, sorted according to their position in the wiring diagram: Mod Item Replacement In Diagram? Stock Antenna Lead Delete Yes Stock Antenna Lead Delete Yes Stock Water tank Yes Upgrade Side Marker Lamp RH LED Bulb - Front Turn Signal Yes Upgrade Inspection Light LED Bulb - Inspection Light Yes Stock Horn Relay Yes Stock Battery Yes Stock Accessory Relay Yes Stock Choke Switch Yes Upgrade Map Light LED Bulb - Map Light Yes Stock Rheostat Yes Stock Fuel Pump Yes Stock Defrost Relay Yes Upgrade Glove Box Light LED Bulb - Glove Box Light Yes Upgrade Room Light LED Bulb - Dome Light Yes Upgrade Room Light Yes Stock Tank Unit Yes Stock Step Light RH Yes Upgrade Side Marker RH LED Bulb - Red Marker Light Yes Upgrade Rear Combination Light RH LED Bulb - Brake Light Yes Upgrade Rear Combination Light RH LED Bulb - Rear Turn Signal Yes Upgrade Rear Combination Light RH LED Bulb - Reverse Light Yes Upgrade License Light RH LED Bulb - Plate Light Yes Upgrade License Light LH LED Bulb - Plate Light Yes Stock Heat - Glass Yes Upgrade Rear Combination Light LH LED Bulb - Brake Light Yes Upgrade Rear Combination Light LH LED Bulb - Rear Turn Signal Yes Upgrade Rear Combination Light LH LED Bulb - Reverse Light Yes Stock Auto Antenna Delete Yes Stock Antenna switch Repurpose ??? Yes Stock Side Marker LH Yes Stock Step Light LH Yes Stock Comb. Switch Yes Stock Hand Break Switch Yes Stock Speedometer Yes Stock Tachometer Yes Stock Oil Pressure / Water Temp Yes Stock Fuel Gauge / Ammeter Voltmeter Yes Stock Clock Yes Stock Choke Warning Light Yes Stock Defrost Switch Yes Stock Seatbelt Warning Light Yes Stock Fog Light Switch Yes Stock Door Switch RH Yes Upgrade Cigarette Lighter 12 volt plug Yes Stock Seat Switch Yes Stock Seatbelt Switch LH Yes Stock Seatbelt Switch RH Yes Stock Neutral Switch Yes Stock Buzzer Yes Stock Door Switch LH Yes Stock Indicator Lamp (Auto T/M) Yes Stock Hazard Switch Yes Stock Ignition Switch Yes Stock Steering Lock Switch Yes Stock Wiper Motor 91 Honda Civic Wiper Motor Yes Addition Wiper Motor Wiper Upgrade Relay No Stock Buzzer Yes Stock Inhibitor Switch (Auto T/M) Yes Stock Air Con Power Yes Addition Air Conditioner No Stock Blower Switch Yes Stock Heater / Blower Yes Upgrade Side Marker Lamp LH LED Bulb - Front Turn Signal Yes Addition Side Marker Lamp LH Side Marker LED Conversion Plugs No Stock Parking & T/S & Side Front LH Yes Upgrade Head Light LH Headlight Projection Housings Yes Upgrade Head Light LH Headlight Projection Housings Yes Stock Horn L Yes Stock Fog Light LH Yes Stock Fog Light RH Yes Addition Front Fog / Rally Light Relay No Stock Horn R Yes Upgrade Head Light RH Headlight Projection Housings Yes Upgrade Head Light RH Headlight Projection Housings Yes Addition Head Light RH Headlight Relay Upgrade Harness No Upgrade Parking & T/S & Side Front RH LED Bulb - Front Turn Signal Yes Addition Parking & T/S & Side Front RH Parking Light Upgrade Harness No Addition Parking & T/S & Side Front RH Parking Light Upgrade Harness, 70-73 No Stock Volt Reg Yes Stock Voltage Regulator Yes Stock Thermal T/M Yes Stock Oil Pressure Yes Upgrade Fuse Box 280ZX Fuse Box Yes Upgrade Fuse Box Long Pigtail Blade Style Fuse Box Yes Upgrade Fuse Box Short Pigtail-Blade Style Fuse Box Yes Upgrade Fuse Box Short Pigtail-Blade Style Fuse Box Yes Upgrade Starter Motor Gear Reduced Starter Motor Yes Stock Fusable Link Circuit Breaker / Fuse Yes Upgrade Radio Stereo Delete Box Yes Stock Reverse Switch Yes Stock T/S Flash SW Yes Stock Four Way Flasher Yes Stock Brake Ind. Yes Stock Ballast Resistor Delete ??? Yes Stock Stop Sw Yes Stock Thermo sw (Auto T/m) Yes Upgrade Alternator Alternator - 100 Amp Yes Addition Alternator Alternator Upgrade Plug No Stock Fusable Link Circuit Breaker / Fuse Yes Stock Thermo Relay (Auto T/M0 Yes Stock Coil Yes Stock Distributor (Manual T/M) Yes Stock Distributor Condenser No Addition Anti-Theft Kit / Alarm N/A Addition Auxiliary Fuse Box N/A Addition Bluetooth Speaker Power N/A Addition Electric Radiator Fan N/A Addition Electric Radiator Fan Pigtail N/A Addition Electric Radiator Fan Temp Control Kit N/A Addition GPS Power N/A Addition Third Brake Light N/A Addition Under Dash / Footwell Lights N/A Addition USB Socket / Phone Charger N/A Upgrade LED Bulb - Dashboard Light Set N/A Stock Fuel Sender Electrical Connector No Stock Electric Fuel Pump Wiring Install Kit Harness Relay No @SteveJ, I don't know if I will be going with the ammeter I have or converting to a voltmeter. I need to look at the pros and cons of that change. In fact, I have not decided if I am keeping the factory gauges at all. This is a restomod and I have already made irreversible changes, so I don't know. I might also address the 9-pin switch by backdating that to an earlier version. Any suggestions on other changes anyone has that will make the car better would be much appreciated. I am hoping this thread can turn into a resource for others and not just me tracking my progress. Edited June 5, 20222 yr by Matthew Abate Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-641281 Share on other sites More sharing options...
June 5, 20222 yr comment_641284 A wonderful and admirable project. My thoughts. ditch the ammeter, voltmeter only. No need to have lots of high current wire running around with no purpose. and go aftermarket gauges without doubt. Don’t forget the AFR gauge as well. Vendors make 3d printed adapters for speedhut gauges for S30’s. Join the world of Deutsch connectors and/or weatherpack. Relatively small investments and easy to crimp and make waterproof connections. Like the brake line world, once you invest in the tooling (good pair of crimpers), all wiring issues become simple to handle rather than a pain in the, well you know. Since you still need to interface to OEM components, vintageconnections.com has many of the stock pins and connector shells you need. Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-641284 Share on other sites More sharing options...
June 5, 20222 yr Author comment_641286 Thanks @zKars! I'll take your comments into account. I was already leaning toward Deutsch or Weatherpack connectors. The gauges I had not considered changing due to the lack of dual options out there, but I'll look around. In addition to suggestions for adding or swapping things, if anyone sees anything on my list that they think I should take off, please let me know. For example, I had someone tell me to ditch the electric fan and keep the original, but I am not sure about that because I am going to add air conditioning. Edited June 5, 20222 yr by Matthew Abate Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-641286 Share on other sites More sharing options...
June 6, 20222 yr comment_641289 I used weather pack in my harness and I’d recommend them. Easy to crimp and pin…and de-pin! The only downside to them is they’re bulky. I used the 280 series if I recall correctly and the 6 pin isn’t small. I do know they have slimmer series though up to 12 pin I believe. But for the large bulkhead connectors I used a molex style. Deutsch has some nice connectors, especially if you want the whole chassis to be the same connector style. Definitely get a quality crimper!! For wiring I went GXL. I felt it provided sufficient coverage for regular driving. 11 colors was enough diversity for me to not get mixed up. But I did remove alot of the OEM options (door lights, buzzers, safety, etc). Wirebarn was a good source for this. Check out my build thread for more details on it and feel free to ask any questions! Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-641289 Share on other sites More sharing options...
June 11, 20222 yr Author comment_641408 I went through the wiring diagram I have, which I downloaded from this site, and captured the wire colors running to each component in the stock system. I am planning to use this list to figure out what color wire to change to when I am unable to source wiring in the stock colors, but I thought I would post it here for anyone who wants it. Item OEM Wire Color Water tank • Black • Black w/ Yellow Side Marker Lamp RH • Black • Green w/ Blue Inspection Light • Ground • Red w/ Blue Horn Relay • Green • Green w/ Black • Green w/ Red Battery • Black • Black • Ground Accessory Relay • Blue • Black • White w/ Red • Blue Choke Switch • Black • Red w/ Blue Map Light • Black • Red w/ Blue Rheostat • Green w/ White • Red w/ Blue Fuel Pump • Yellow • Black Defrost Relay • Blue w/ Red • Black • White w/ Red • Red w/ Black Glove Box Light • Ground • Red w/ Blue Room Light • Black • Red w/ Blue Tank Unit • Yellow • Black Step Light RH • Black • Red w/ Blue Side Marker RH • Black • Green w/ White Ground • Black Rear Combination Light RH • White w/ Black • Green w/ White • Black • Red w/ Black Rear Combination Light RH Rear Combination Light RH License Light RH • Black • Black License Light LH • Black • Black Heat - Glass • Red w/ Black • Black Rear Combination Light LH • White w/ Black • Green w/ White • Black • Red w/ Black Rear Combination Light LH Rear Combination Light LH Auto Antenna • Blue w/ Red • Blue w/ White • Black • Antenna Lead Antenna switch • Blue w/ Red • Blue w/ White • Blue Side Marker LH • Black • Green w/ White Step Light LH • Black • Red w/ Blue Comb. Switch • Green w/ Blue (1) • Green w/ White (2) • White w/ Red (19) • Black (3) • Blue w/ Yellow (4) • Blue w/ White (5) • Red (20) • Blue (6) • Red w/ Blue (7) • Blue w/ Red (8) --- • Green w/ Yellow (9) • White w/ Red (10) • White w/ Black (11) • Green w/ Red (12) • Green w/ Black (13) • White (14) • Red w/ White (15) • Red w/ Black (16) • _____ (17) • Green w/ Black (18) Hand Break Switch • Ground • Yellow w/ Blue Speedometer • Red w/ Blue • Red w/ Blue • Red • Red w/ White • Yellow w/ Blue • Red w/ Blue Tachometer • Green • Red w/ Blue • Green w/ Black • Green w/ White • Black w/ White • Green w/ Red • Red w/ Blue • Black Oil Pressure / Water Temp • Black • Yellow w/ White • Green to Yellow w/ Red • Red w/ Blue • Green to Yellow w/ Red • Yellow w/ White Fuel Gauge / Ammeter • White w/ Red • White • Red w/ Blue • Yellow • Green to Yellow w/ Red • Black Clock • Black • Red w/ Blue • Blue Choke Warning Light • Red w/ Blue • Red Defrost Switch • [MISSING] • Blue w/ Red • Blue Seatbelt Warning Light • Black • Green Fog Light Switch • Red • Red w/ Green Door Switch RH • Black • Black • Ground Cigarette Lighter • Blue w/ White • Black Seat Switch • Red • Green w/ Black Seatbelt Switch LH • Green w/ Black • Green Seatbelt Switch RH • Green • Green w/ Black Neutral Switch • Green • Green Buzzer • Green • Black Door Switch LH • Black • Black • Black • Black • Ground Indicator Lamp (Auto T/M) • Black • Red w/ Blue Hazard Switch • Green w/ White (1) • Green w/ Red (2) • Green w/ Black (3) • Green (4) • Green (5) • Green w/ Yellow (6) • Green w/ Yellow (7) • White w/ Black (8) • White w/ Red (9) Ignition Switch • Black w/ Yellow (1) • Black w/ White (2) • White w/ Red (3) • Blue w/ Red (4) • Green w/ Blue (5) Steering Lock Switch • Red • Black Wiper Motor • Black (E) • Blue w/ Red (B) • Blue (L) • Blue w/ White (M) • Blue w/ Yellow (H) Buzzer • Yellow • Red Inhibitor Switch (Auto T/M) • Black w/ Yellow • Black w/ Yellow • Red w/ Black • Red Air Con Power • Red to Blue Blower Switch • Red • Black • Black Heater / Blower • Red • Black • Black • Ground Side Marker Lamp LH • Black • Green w/ Blue Parking & T/S & Side Front LH • Black • Green w/ Red • Green w/ Blue Head Light LH • Red w/ Black • Red w/ White • Red w/ Yellow Horn L • Green • Ground Fog Light LH • Black • Red Fog Light RH • Black • Red Horn R • Green • Ground Head Light RH • Red w/ Black • Red w/ White • Red w/ Yellow Parking & T/S & Side Front RH • Black • Green w/ Blue • Green w/ Black Voltage Regulator • Black (E) • White (A) • White w/ Black (F) • Yellow (N) • _____ (L) • _____ (–) • Black w/ White (IG) Thermal T/M • Yellow w/ White • Ground Oil Pressure • Yellow w/ White • Ground Fuse Box • Green w/ Red (H) • Green w/ Yellow (S) • Red w/ Blue (PT) • Red w/ Blue (PL) • Red (HR) • Red w/ Yellow (HL) • Blue w/ White (C) • Blue (A) • Blue w/ Red (W) • _____ (F) • Black w/ White (IG) • Blue w/ Red (C) • _____ (–) • _____ (–) • _____ (–) • Red (–) • White w/ Red (A) • White w/ Red (A) • _____ (–) • White (B) Starter Motor • Black • Black • Black w/ Yellow • Ground Fusable Link • Black Radio • Ground • Black • Red w/ Blue • Antenna Lead Reverse Switch • Red w/ Black • Red Turn Signal Flash Switch • Green • White Four Way Flasher • Blue w/ White • Green w/ White Brake Indicator • Yellow w/ Blue • Ground Stop Switch • Green w/ Yellow • Green w/ Yellow Ballast Resistor • Green w/ White • Black w/ White Thermo sw (Auto T/m) • Black w/ White • Green Alternator • Black (E) • _____ (A) • White w/ Black (F) • Yellow (N) • _____ (–) • _____ (–) • _____ (–) • _____ (–) • _____ (–) • _____ (–) • Fusible Link (A) • Black (E) Fusable Link • White w/ Red Thermo Relay (Auto T/M0 • Green • Black • Black • Red w/ Black to Black Coil • Black • (To Distributor) Distributor (Manual T/M) • Black • (From Coil) Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-641408 Share on other sites More sharing options...
June 11, 20222 yr Author comment_641432 Also, I found this helpful in understanding what we are dealing with here: Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-641432 Share on other sites More sharing options...
June 16, 20222 yr Author comment_641581 I have some noob questions maybe some of you can help me out with: Is it better to build the wiring for mods into the main body harness or make a separate one that attaches to the main one, given I am starting from scratch? Can I somehow repurpose the Thermo Switch / Thermo Relay for an automatic transmission to control my electric radiator fan? Could I repurpose the wires for the automatic antenna and antenna switch for anything, like power for a Bluetooth speaker, for example? Could I repurpose the wires for the Inhibitor switch for an automatic transmission for anything? Could I repurpose the wires for the indicator lamp for an automatic transmission for anything? Edited June 16, 20222 yr by Matthew Abate Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-641581 Share on other sites More sharing options...
June 17, 20222 yr comment_641584 If I was to rewire a car I would be looking to use a PDM - power distribution module also called PMU. They are a solid state device that simplifies wiring and does away with the traditional fuses. it allows for peak current management, retries if current exceeded, logic, timers, etc. There are a few on the market. If you were also going to change the gauges, look at CANbus gauges. They can integrate with the PMU. The PMU would also allow you to change inputs and outputs so you could repurpose beore or after installed. The PDU's cost a bit but you save on wiring and the time to install. https://www.ecumaster.com.au/products/ecumaster-pmu The PMU route is a bit of a rabbit hole as is CANbus, but does modernise the entire setup. Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-641584 Share on other sites More sharing options...
June 17, 20222 yr Author comment_641585 This is super cool! It also sort of negates the reason I got a 240z, which is to have a car with no computer that I can fix myself. It also costs 2/3rds what the car cost me. I am looking at going with a more modern ignition system though… Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-641585 Share on other sites More sharing options...
June 18, 20222 yr Author comment_641628 Okay. Made a nail board… It’s flimsy and probably too small, but it fits in my home office so I can theoretically work on this when it’s crazy hot out. I’m hoping that makes the project more likely to move forward. Edited June 18, 20222 yr by Matthew Abate Link to comment https://www.classiczcars.com/forums/topic/67523-1973-240z-custom-wiring-from-scratch/#findComment-641628 Share on other sites More sharing options...
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