how to modernize car wiring

[G_Body_Enthusiast]

I want to add relays for the headlights but I also want to add relays for other circuits like the dash lighting, brake lights, etc. And while it's not too hard to add relays into most circuits, I'm thinking I'd like to rewire the car with relays and such already built into the harnesses. Are there replacement connectors for the bulkhead for the engine compartment? I'd like to start simple and do just the headlight wiring first and do a single circuit at a time after that.

Almost all of my wiring is still in excellent condition, the engine wiring has some issues but nothing terrible. I just figure 30 years on copper wiring is going to lead to some parasitic loss.

 

[565bbchevy]

I still have my factory wiring in tact and my fuse box has no additional wires or add ons coming from it since I added two 12 circuit fuse panels that are wired separately from my stock wiring.
I have one fuse panel wired to the battery side and the other for ignition side and anything high amp has it's own relay. all of my fans, electric water pump, etc. are wired into these fuse panels.
I also have two 6 circuit fuse panels one is in the trunk wired directly to the battery for things like fuel pump and nitrous bottle heater etc. and the other one is under the dash for all the nitrous functions all of which have relays.
I also have a remote solenoid for the starter and 2 other bulkheads that I can tap into for power.

 

[G_Body_Enthusiast]

Ok, you're running things I'll probably never run, like nitrous. I may run a fuel pump if I go to EFI at some point but making a circuit for it with relays and fuses isn't that difficult. I'm wondering if anyone has rewired their cars original circuits and with new wires and additional parts like relays.

I may end up redoing everything including the fuse box just so add-ons like EFI will be more of a clean installation. Since the car was pretty much virgin when I bought it, I'm the only one who has done aftermarket modifications to it like an electric fan. So when I do electrical work on the car, I like for the work to look clean and well thought out. I've seen too many cars with hacked up harnesses, bad grounds and worse and I don't want my car to look like that. I could make the relays plug and play like some aftermarket companies do but the car will still have 30 year old wiring in it. I'm trying to address the necessity of adding relays while addressing the issue of aging wires with who knows how much resistance from age and what not.

 

[drogg1]

issue of aging wires with who knows how much resistance from age and what not.

Is it an issue? I don't know that you can assume they have higher resistance enough for it to matter. Most circuits don't draw enough current anyways.

You could check the resistance of the power wires for the higher current circuits like for the headlights with a multimeter if you wanted to know.

I have a hard time believing the wires have oxidized enough to gain a significant amount of resistance but I can see how you might want to do it for a cleaner appearance perhaps.

 

[L92 OLDS]

I may run a fuel pump if I go to EFI at some point but making a circuit for it with relays and fuses isn't that difficult. I'm wondering if anyone has rewired their cars original circuits and with new wires and additional parts like relays.

I may end up redoing everything including the fuse box just so add-ons like EFI will be more of a clean installation. Since the car was pretty much virgin when I bought it, I'm the only one who has done aftermarket modifications to it like an electric fan. So when I do electrical work on the car, I like for the work to look clean and well thought out. I've seen too many cars with hacked up harnesses, bad grounds and worse and I don't want my car to look like that. I could make the relays plug and play like some aftermarket companies do but the car will still have 30 year old wiring in it. I'm trying to address the necessity of adding relays while addressing theissue of aging wires with who knows how much resistance from age and what not.

Here's a thought and an approach I think makes sense. Guys doing LS swaps that need relays for an ECM, fuel pump, fans, AC compressors, etc. and also need fused under hood circuits (O2 sensors, Ignition coils, etc etc) are using "smallish" fuse blocks from mid 90's GM cars. These could also replace the crappy fusible link set up our G body cars have while retaining the factory fuse panel in the interior of the car.

 

[G_Body_Enthusiast]

Is it an issue? I don't know that you can assume they have higher resistance enough for it to matter. Most circuits don't draw enough current anyways.

You could check the resistance of the power wires for the higher current circuits like for the headlights with a multimeter if you wanted to know.

I have a hard time believing the wires have oxidized enough to gain a significant amount of resistance but I can see how you might want to do it for a cleaner appearance perhaps.

While I know this is an extreme example because no other circuit in the car operates like this...over time resistance builds up in the battery cables over time. Enough can build up that it can cause the car to have problems starting. That and there's the more common problem of the insulation becoming brittle and exposing wires. There is the issue of parasitic loads, draining the battery. Bad grounds that need to be fixed. It's more than a build up of resistance in the wires to replace the wiring with new wiring.

 

[pontiacgp]

I would change the rear harness from the fuse box to the rear lights to copper wiring. GM used single strand aluminum wires that will break if you try to tap into the wire and can corrode faster than the copper wires. I had the rear lights brown wire break right at the fuse box from corrosion and it was no fun to try to fix that at the side of the road when I got pulled over for no tail lights.

 

[G_Body_Enthusiast]

I would change the rear harness from the fuse box to the rear lights to copper wiring. GM used single strand aluminum wires that will break if you try to tap into the wire and can corrode faster than the copper wires. I had the rear lights brown wire break right at the fuse box from corrosion and it was no fun to try to fix that at the side of the road when I got pulled over for no tail lights.

So the entire harness to the back is like this? Guess I'll start with that first, along with the addition of a third brake light and other upgrades. A trunk light would be nice too.