Need help figuring out wiring
 

I am a novice when it comes to electronics. I know a bit, but would like some assistance with my project for this weekend. (This is on a 79 btw.)I believe my fuel pump wiring is shorting out where it goes from the interior of the car through the hole to the outside of the car and connects to the pump. I am guessing the gromment is gone and has rubbed through the insulation causing that wire to short out. My main engine fuse heats up and my car turns off while driving. Not very fun when this happens on interstate.

My plan for this weekend is to run new wire from the fuel pump into the car, putting in a new gromment to save the wire. In the car, I want to wire it up to a switch for security because my car has no locks at the moment. From the switch, I want to have it on its own fuse (probably right next to the current fuse block). Also, I would like to wire up a LED so that I know when my fuel pump is on or off.

My questions:

Which wire should I tap off of before the fuse block for this new fuel pump wire?

Should I use a 20amp fuse or go lower?

How should I run the LED? Should I use a t-connector and splice it in, or should all of the power be running through it?

Thanks for your help.

If I understand you correctly, you want a fuel cut-off switch. Usually that's a single on/off switch, so no LED is required unless you just want it.

If the power going to the fuel pump is 12v, then a 20amp sounds like it SHOULD be sufficient. But there are plenty of guru's here that will be quick to correct me if I am wrong.


IF this is what you're speaking of, then this link might help a bit:
https://www.rx7club.com/showthread.p...uel+pump+relay

~Jerry

Oh, forgive me....I cut and pasted the wrong link, let me go find the write one....

Damn, I can't spell today.


Here's the link I meant to post: https://www.rx7club.com/showthread.p...+cutoff+switch


~Jerry

That isn't really what I am looking at doing but thanks for the link. I am going to replace the wiring from the fuse block to the pump itself. I am going to have the switch in a "secret" spot to deter theft. I want a LED somewhere (probably on the dash) so that I can make sure I have the pump turned on when I go to start the car. Thanks

Find the fray in the wire, cut it there, take the front side of it to your hidden switch, then add new wire back to the cut, along with a grommet and spice back in. Simple, no need to rewire from the fuse block and maintains the stock fuseing.

Thanks, but you still aren't answering my question. I want to replace all of the wiring because the wire is old and who knows where else it will fail. trochoid, your solution still doesn't tell me how to hook up the LED and I want it switched for safety. Let me try asking my questions again:

1: What wire do I need to splice off of (before the main fuse block) to send power to the fuel pump?

2: In wiring up a LED on the dash so I can tell that the pump is on, should I use a T-connector off the main wire or should all of the power be going through the LED wiring?

i believe the relay for the fuel pump is a 30amp, but ionno fo sho'

I'm not up on the specs, requirements or limitations on leds, but, I would wire it in the path with the switch, on it's way to the relay. Pull the power for the relay off of the wire that goes from the ignition switch to the stock relay. Remove the stock relay and install a new one.

In the fuse block, I believe it is the engine fuse that powers the fuel pump.