Stock wiring

[kev2809]

finally got a donor truck for my ls swap. i never considered rewiring my suburban, but what are u swap guys doing for wiring. im not referring to the engine harness, i mean the actual truck wiring. im thinking of getting the EZ wiring 21 wiring kit, but unsure if its needed with an ls swap. i havent really tested my original wiring, but figured for their price it would be a good idea to replace my old original one. or are most just using thr stock truck wiring?

[ls1nova71]

If the factory wiring to the rest of the truck, everything but the engine, is bad, then you will need to do something about it. An LS swap wiring harness just runs the engine.

[kev2809]

i figured fresh wiring would be a plus for the newer motor. what stock wiring does the ls motor tie into?

[ls1nova71]

Originally Posted by kev2809

i figured fresh wiring would be a plus for the newer motor. what stock wiring does the ls motor tie into?

Fresh wiring wouldn't hurt in a 50 year old vehicle. But if your wiring is in great shape, it's not 100% necessary. The LS harness ties into the truck harness in a couple of places, the main one being the ignition power that powers up the LS harness. The LS harness should have a main ignition relay that powers up the rest of the harness, then your original distributor power wire will turn on that relay, that way you are not putting the whole engine harness load through the original ignition switch that wasn't designed to handle that kind of load. People skip the relay from time to time, and it may work for a while, but isn't good practice, and could potentially overload the ignition switch and burn the vehicle to the ground, so in my opinion, just not worth the risk.

There are other wires like gauges, torque converter lock up, and fuel pump that will need to be hooked up too, but most of that doesn't have any affect on the vehicle harness.

[kev2809]

Originally Posted by ls1nova71

Fresh wiring wouldn't hurt in a 50 year old vehicle. But if your wiring is in great shape, it's not 100% necessary. The LS harness ties into the truck harness in a couple of places, the main one being the ignition power that powers up the LS harness. The LS harness should have a main ignition relay that powers up the rest of the harness, then your original distributor power wire will turn on that relay, that way you are not putting the whole engine harness load through the original ignition switch that wasn't designed to handle that kind of load. People skip the relay from time to time, and it may work for a while, but isn't good practice, and could potentially overload the ignition switch and burn the vehicle to the ground, so in my opinion, just not worth the risk.

There are other wires like gauges, torque converter lock up, and fuel pump that will need to be hooked up too, but most of that doesn't have any affect on the vehicle harness.

nice, ill look over my original and see what to do. ive read through 17 pages so far of this LS sub forum and trying to get somewhat of an idea of how these swaps work. im trying to keep costs down as much as possible, ive had my truck 11 years and drove it once. im tired of it sitting. ordered my dirty dingo slider mounts yesterday, plan on rewiring the stock engine harness myself. thats all i got planned out so far

[b454rat]

I've been reading up on swaps, and once the LS side has been done, there is only 4 wires I think that need to be hooked up to the truck. So the trucks stock wiring should be fine. Prolly have to change some sensor plugs or similar to use the trucks wiring to fit on the LS plugs.

[gmc684x4]

You can cut the top of the oil sending unit and tap it to fit your oil sending unit tube
Easy to drill passanger side head for temp sending unit
That is unless you plan on going dakota guages with the blm modual to take guage info from the ecm

Question is how hood are you at wiring as those kits are other then the bulkhead 100 % do it your self

M&H makes factory style harness like original that is modular that you can tailor to replace only the sections that are really rough

[LS short box]

On my 68 C10 LS swap I used a Painless universal kit for the chassis. Howell Fuel Injection for the LS and trans harness.
I don't trust 50 year old wiring. I cut the original chassis connectors off and then used them with the Painless harness as needed. LS swaps need good connections and really good grounds to function properly.
Good luck with your swap.

[kev2809]

they seem decent to me?

[ls1nova71]

I would probably consider replacing that harness, there is an awful lot of rust on the fuse connectors which most likely wont clean off and could cause problems,

[kev2809]

Originally Posted by ls1nova71

I would probably consider replacing that harness, there is an awful lot of rust on the fuse connectors which most likely wont clean off and could cause problems,

ya i never noticed it until the flash went off on my camera, plus i hate those glass type fuses. i think i will try the EZ Wiring 21 circuit kit