View Full Version : Interior wiring replacement.

04-19-2012, 11:01 PM
What are you guys doing with your interior wiring during your swap? Awhile back I thought I read somewhere that the old stock wiring wasn't set up for the higher amperage of the LS alternators. Is anyone buying a Painless style harness and swapping out their stock fuse block and wiring? I would like to upgrade my wiring from these old wires to something more up to date but I'm not sure who has the best kit. Who would you recommend? Thanks in advance.

04-19-2012, 11:21 PM
What is it you want to accomplish?? Re-wire for the Alt issue, or re-wire the whole car and how old is the car??.
The older cars had an amp gauge and alt at that time 37-61 amps, your new one could be as big as 140 or small as 105, that toasts the amp gauge..:usa:

04-20-2012, 06:22 AM
If the actual chassis harness is in good shape you can reuse it. The engine and charging system wiring needs to be updated. If you get a GM chassis manual to find your wiring diagram, then simply un pin the circuits you no longer need. I did this and it all works just fine.
If you look a current vehicles you will find that the bulk of the wiring is done with 18-22 ga wire, where your car is 14-18, way more than capable of handling the current.
I agree with oldngray about the amp meter, they are a fire waiting for a place to happen.

garys 68
04-20-2012, 08:02 AM
If you're trying to run high amperage items like dual electric cooling fans through the fuse panel, you'll most likely cook it. I even found an aftermarket panel was heating up with everything on.
I rewired both my cars simply because the harnesses were 40+ years old and had been spliced into a few hundred times. But if you're harness is ok and you're not running a lot of extras through it, you'll be ok.

04-21-2012, 05:46 PM
I have a 72 Cutlass that I hope to be starting to tear down soon and I would like to rewire it just so I know the wiring is good. Lighting harness I will most likely keep. Things like dash control components I will probably inspect the wiring and reuse it. I am planning on installing a newer instrument panel cluster so I will be rewiring everything to it. I would like to get rid of the old glass fuse block for an up to date block. The engine harness is the stock LS1 Corvette harness. I haven't decided if I want to run A/C or not. I would have to upgrade my system since my car originally came with A/C.

garys 68: I'm going to try and run the Windstar fans like you did so that's also why I want to upgrade the wiring.

garys 68
04-22-2012, 02:48 AM
On my build I upgraded the size of the wire feeding the fuse block. But I fed the power to the fans at the opposite end of the copper strip that runs through the block.......Mistake. The current running through the strip caused the block to get warm. It would have been fine if I spliced off the feed wire.

04-22-2012, 10:49 PM
You used the positive power post on the fuse block when you shouldn't have? How did you run power to the fans then? Where'd you get your fuse block?

04-23-2012, 12:16 AM
As pointed out stock wiring in good condition is good if not better than repro stuff since it's often larger ga wire. Now if the underdash harness looks like a spaghetti night special with an extra helping of butt connectors by all means replace it. Some don't like glass fuses, I actually prefer them since you can see when they're blown.

Even on good stock wiring I like to convert existing high draw loads onto relays instead of stock switches, just like new cars/trucks. Headlights, convertible tops, etc. New high amp loads like cooling fans should be powered independently of the in-car fuse block.

tfi racing
04-23-2012, 03:25 AM
About a year ago I replaced a rusted out fuse box on a 68 442-thats right,from the front it and the fuses looked fine,but the buss bars on the backside were long gone!I used a universal box from Painless,it actually mounted using the stock screws and location and wasn't terribly difficult to swap over.

garys 68
04-23-2012, 08:02 AM
I bought a generic aftermarket fuse panel.
I fed one end of the copper strip in the fuse block from the alternator/battery. On the opposite end of the strip I fed power to the 4 relays (2 fans, fuel pump, horn). Bad idea since the highest amp draw went through the strip. If I had fed the relays from the feed wire at the other end, there would have been no issues.
You used the positive power post on the fuse block when you shouldn't have? How did you run power to the fans then? Where'd you get your fuse block?