Jb280z Posted August 5, 2014 Share Posted August 5, 2014 My first post here, however I have been browsing hybridz for almost a year now. So when I first started my build, 75 280z rb25, I made what I think now was a big mistake. I ripped out all the engine bay plugs and wires I thought I wouldn't need from the passenger side harness. (Shunt, voltage regulator, ac control, ect. Everything but the lights, and wipers). Now all I have left is a handful of white/red stripe and plain white wires going into the firewall. Now I am getting an engine harness made by wiring specialties and a full set of new guages. My question is which wires going through the firewall on the passenger side need constant power? Just want to know how much trouble I'm really in for my mistake. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 5, 2014 Share Posted August 5, 2014 One of the great benefits of owning a Z over other old sports cars is that there are wiring diagrams and service manuals all over the internet, free for opening, saving and/or downloading. You're going to need more than just knowing "constant power" wires. Use the Google with the right words. Search classiczcars.com and you might find the full-color versions. Quote Link to comment Share on other sites More sharing options...
Jb280z Posted August 11, 2014 Author Share Posted August 11, 2014 I have been referring to the wiring diagram. However, when trying to trace from the battery/ alternator back into the firewall I'm getting stuck at the voltage regulator. I'm assuming the fuse box needs a large guage feed wire. But other than that I'm not sure. For what it's worth I'm not using heater or ac and have no need for the shunt. Quote Link to comment Share on other sites More sharing options...
zster Posted August 13, 2014 Share Posted August 13, 2014 I tore all of that stuff out you probably won't need it with a RB. Download fsm and check what wires feed your fuse box. My fuse box is for lights and signals. The engine has new wiring kind of separate from the car. Quote Link to comment Share on other sites More sharing options...
wrcbonk Posted August 13, 2014 Share Posted August 13, 2014 You only need a handful of circuits from the old stock engine harness. I would turn the fact that you scrapped the existing stock engine harness as a positive, it will help clean up your enigne bay. I left the stock engine harness in place and most of it is dead weight and looks crappy. Another member found this website http://vintageconnections.com/ These guys should hopefully have everything you need to make a paired down stock-like engine harness that you can reconnect to the interior harness behind the fire wall. There are several circuits from the stock 240z enigne harness you will want to have in your paired down harness. Zster mentioned lights and signals. Hopefully you have converted to a newer headlight harness that only uses the stock harness to "switch" not "drive" the circuits. As you indicated yo ualso need wipers and washer pump curcuits. I used the oil pressure sensor wire, the temp gage wire, and the coil "hot when on" wire to control the thermostatic switch for my fans. You don't need the starter solenoid that comes in the RB harness. You can use the red/white wire off the RB harness for the alternator charge light. You may want the horn circuit, I use it. I will try to check and see if I am using anything else. I managed to navigate around the whole voltage regulator/shunt thing because I am using an after market harness. Its cheating, I know. I made a fuse block using a blue-sea. Its fine when centralizing minor circuits like stereos, the interior harness, sensor wires (wide-band), or any other accessories, BUT I would not recommend using it for major circuits like electrical fans, I melted a terminal on the blue-sea early on with the fans. If I had to do it all over I would buy another high amperage capacity fuse block and wire essentials like lights and fans to that seperately. Also, I've been meaning to replace my atc blade fuses with blade circuit breakers for a while now. I hope my ideas are focussed on where you are trying to get help. Bill Quote Link to comment Share on other sites More sharing options...
zster Posted August 14, 2014 Share Posted August 14, 2014 I put up a junction box with constant hot, switched hot and ground near the fire wall. The white/red wires going to fuse box were connected to hot. Make sure you have it fused. Quote Link to comment Share on other sites More sharing options...
ZT-R Posted August 16, 2014 Share Posted August 16, 2014 Wiring specialies. Best money spent. ( i have a chase bays, but i wouldn't do that again...) wiring is so simple now, its awesome. Quote Link to comment Share on other sites More sharing options...
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