Jump to content

IGNORED

Wire Harness Question


87mj

Recommended Posts

I am in the process of restoring a '70.  I have gutted it and am in the process of putting it back together.   My next step is to install a new dash.  I have moved the dash wiring harness to the new dash along with all the gauges and I am about to plug everything back into the harness.  The engine is still out of the car.

I am about to plug a battery into the harness so I am very intimidated at the thought of burning something up.

My ground is connected correctly.

Assuming I am careful and connect the electrical components back together such as the lights, horns, etc. so that nothing is touching metal that shouldn't, I see there are 3 wires coming off the positive battery terminal.  One is a thick black wire which goes to the starter.  I assume that powers the starter motor.  Since there is no starter right now, I assume I can put that one aside.  That means there is a smaller gauge black wire going to the solenoid  and another going to the fusible link.

If I wanted to apply power to the harness to test the lights, horns, gauges and so on, is it safe to say I only need to apply power to the wire with the fusible link?

I also thought I would pull all the fuses from the fuse box except the circuit I am testing.  That should eliminate any chance of burning everything up. Agree?

Any suggestions?

Link to comment
Share on other sites

Put one of these in the power supply line from the battery.  A 20 amp fuse (or 10 if you want to be really cautious) should protect any of the wires in the harness.  If it blows right away you have a short.  As you turn on various lights and gizmos and it blows you'll have a clue about which device has a problem.

The 240Z owners manuals have good wiring diagrams in them.

https://www.autozone.com/electrical-and-lighting/fuse-and-accessories/bussmann-atc-fuse-holder-with-cover/32415_0_0?spps.s=4180&cmpid=LIA:US:EN:AD:NL:1000000:ELC:71700000060662503&gclid=CjwKCAiAn7L-BRBbEiwAl9UtkHW6xyqKPANG2FaYsa9znpvCznDnG5GjjBuOLa2uPpPq0ebehc1UzBoCzqQQAvD_BwE&gclsrc=aw.ds

image.png

Edited by Zed Head
Link to comment
Share on other sites

I think that you might have to ground the potentiometer (dash light dimmer) circuit to get the lights to work.  It might ground through the dash frame.  Gotta have a ground.

Last thing - measure resistance through the circuit from power supply to ground before you apply power and you'll know if you have a dead short before you even blow any fuses.

Edited by Zed Head
Link to comment
Share on other sites

When I first re-connected power after my car sat in my garage for 20 years, I pulled all the fuses and connected a trickle charger instead of an actual battery. It's limited to 3 amps, so seemed pretty safe. I then added one fuse at a time and tried each circuit. Surprisingly, the 3 amps was enough to do a high level check on a lot of the circuits. Once I'd done that, I pulled all the fuses again and connected the battery and repeated the process. Prior to doing all that, I'd spent quite a bit of time at the back of the car repairing wiring that had been chewed by mice, so I was pleased to find that everything worked.

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.