sideways-FC

I have two electrical questions. the first one is I am removing all the wireing out of my car I dont need any more like for heating and ac suff, power streering computer, cruise control computer stuff like that but I am keeping all my wires that have 12volts when I turn the ignition on, and all my illumination wires so I can use them to wire up relays and gauges and stuff like that but some of the wires I can only read 12volts on when I ground them at the ignition switch, and some I only get a reading on when I ground them to the battery - post and some I dont get a reading on when I ground them to the battery - post and none read any volts when I ground them to the body of the car why would this be? my second question is how do I know if a wire is an illuination wire?or is an illumination wire one that just gives voltage when I turn all the dash lights on? wich currently my dash lights and marker lights dont work either if any one know why that could be that would also be very helpful.

RobbyWally

iTrader: (2)

You are planning to physically remove unwanted wires? Or just disconnect them?

The wiring harnesses are pretty complicated and all of the systems are mixed together. To actually remove the wires you think you don't want or need, you would have to pull out the harness and pretty much disassemble to remove the wires. You car, your choice. Seems a lot easier to just disconnect and remove the hardware and leave the wires in place.

As far as knowing which wires are ok to disconnect or remove, I am fascinated by you thinking you don't need a wire unless it has 12 volts when the ignition is on. What about all the ground wires? You might want to think this through a little bit before you start clipping and ripping. Ready for a familiar line? The FSM includes detailed wiring diagrams with wire color and connector configuration.

sideways-FC

I am just cliping off all the unneeded wires were they come off of the main harnesses and leaving like 2 to 3 inches and taping them againsed the main harnesses with electrical tape and 12volt switched wires and illumination wires I can use I think I will run somewhere under the dash so I can have them handy when I need to wire stuff up that requires them. I can make my own grounds no point in haveing a bunch of wires running along the harness that I can just ground to the body of the car. the interier of the car is going to be stripped prity much no carpets no sound deadoning no trim the interior will be painted white and its just going to be the driver and passenger seats the basic dash wich I will be painting black, and the battery will be behind the passenger seat and I dont want all those wires hanging around from stuff I dont have or need any more its a gxl theres a lot of them, and I figure I can use a few of those wires to wire up things I will be having in the car like gauges and relays.

Watase

I wouldn't necessarily suggest just taping them.. electrical tape isnt the worlds longest lasting tape if heat is involved. You might want to use something like heatshrink around the ends then tape them together. Wouldn't want some of that tape to come apart and have the wires possibly short on anything.

But then I'm overly paranoid about stuff like that, haha.

RobbyWally

iTrader: (2)

I still don't get the point of cutting the wires. If you're leaving the wires in the car, you're not saving weight. And any system you're not using isn't using power. So, you're not saving power. Not to mention the risk of seriously jacking your car by cutting wires you think you don't need. For example, several circuits have multiple switches or relay contacts in series. You might have 12 volts only at the first load point of the circuit. Everything else would be 0 volts. Doesn't mean you don't need all those wires to make the circuit work properly.

But, like I said...your car, your choice.

sideways-FC

dude there are like no systems left in my car that I would need to worie about screwing up by cuting wires. like 80-90 percent of what all the electrical **** in the car controled is gone. its just the main fuse blocks in the engine bay, and to the left of the clutch, and the cpu to controle the cars lights, and the stock gauge cluster. all most all the relays in the car are going away to. the engine will be suported by a haltech ecu so thats taken care of. and the reson Im not leaving all these wires is because like I said before the interier is going to be stripped out and is going to be painted white Im leaving it that way and there is A LOT of wires for every thing that would be visabule and that would look like ****. and theres no point haveing a car full of wireing that has no point being there! and 95 percent of this is in the car so heat is not an issue im heat shrinking the tips and taping them to the harness. maybe I will take some pictures to show you guys what I mean.

RobbyWally

iTrader: (2)

My bad...just sorta assumed you were working on a street car. Whatever works for you, man.

sideways-FC

belive it or not I am going to try and get this car on the streets lol now could someone please answer my origanle question.

RobbyWally

iTrader: (2)

And I'm back to my original answer...use the wiring diagrams in the FSM. There isn't any way to just look at a wire and know whether it is an illumination wire. And, the wiring diagrams for the various lighting systems are the easiest way to trouble-shoot your non-working lights.

About getting 12 v or not depending where you check, the battery negative terminal is a true 0 v reference. Any good electrical contact to the frame should be 0 v, too. The ground points on the body and frame are your best bet. These are identified and located on the Ground Circuit page of the wiring diagram.

The ignition switch delivers 12 v to lots of systems. None of the wires to it are ground wires and the switch body is not necessarily a good ground.

sideways-FC

where do I find the fsm at?

Gasso

From the 2nd Gen FAQ.
Good bookmark to have: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/frequently-asked-questions-2nd-generation-rx-7-faq-fc-494667/

Shop manuals for both series can be found on-line at:
http://www.rotaryheads.com/PDF/2nd_gen/
http://foxed.ca/index.php?page=rx7manual#secondgen
http://mazdarx7.iougs.com/fsm.shtml
http://wright-here.net/cars/rx7/manuals.html

S5 Wiring Diagrams:
https://www.rx7club.com/forum/showthread.php?t=530860

Hope it helps and good luck with your project!

sideways-FC

found it thanks! I will try and figure it out this weekend.

RobbyWally

iTrader: (2)

Yes, thanks to Gasso for providing the links. I didn't include them in my reply because I had already pointed you to both foxed.ca and rotaryheads.com in a reply to your 'striped bolt' problem.

sideways-FC

I think I figured out my problem! the wire on the ignition switch I thought was a ground is actualy a 12v wire. I put the + wire of my meter on the wire on the ignition switch that I thought was a ground then I put the - wire of my meter on the body of the car and I got 12volts. so I gess all the wires I tested and got 12volts on must be grounds.

Gasso

Can you find the wires you are looking at in the wiring diagrams? As mentioned before it's better to use them to determine what you are looking at as opposed to guessing that wires tested are grounds. Have you stripped your interior already? It might be easier to figure out wiring if you start taking some of this out.

My suggestion would be why not build up the car and remove items as needed? You will also have the car in running condition while you are modifying it to do whatever.

sideways-FC

I havent looked at it yet. the interior is completly stripped sound deadoning and everything exept the steering colume. the car hasnt realy ran sins I got it. Im doing the car all at ones engine, ecu, suspenion, electrical stuff, and so on. I feel most of the things in cars are unnecisery,usless, weighs the car down, and over complicates somthing that has no need to be that complicated! I have no problem driveing a stripped and gutted drift car around town! go big or go home!

Gasso

Oh ok, sounds like your really into it already. Keep us posted with how it's going.

+1 for studying these before removing wiring from the car. Any questions... well that's what the forums are for right?

Once again good luck!

sideways-FC

Im going to make a build thread when I realy get in to it in a few months!

Lmill86

iTrader: (10)

That would be great. Electrical work can be costly!

sideways-FC

ok I got the 12v switched wires found but I still dont know how to find my illumination wires I hooked up my head light switch and turned it to on and some wires I found will give me like 9volts with the switch on and 10 volts with the switch off. and I still cant get my illumination/marker lights to work. my headlights work and my brake lights work when I press the brake pedal and my turn signals work. but none of those lights or any of my interear lights come on when I switch the head light/marker light switch on just the head lights come on. I looked at the fsm but im not the best at wiring diagrams. can some one help me out here?

RobbyWally

iTrader: (2)

The light switch in the left side cluster actually has two sets of contacts. One set of contacts controls the headlight relay. The other set controls everything else - tail lights, front & side markers & dash lights. You either don't have power to this 2nd set of contacts or the contacts are worn / dirty.

You can check whether there is power to the circuit at the interior fuse panel. There is a separate 15 amp fuse for the light circuit. If that fuse is good & you have power at the fuse, then it's the switch contacts.

sideways-FC

ok I will check that 2marow or monday. im cuting of my speaker mounts today.