what is needed to incorporate ls harness into stock wiring?

[encasedmetal]

I'm going to be doing a LS swap soon into my 85' C10 and I was wondering once I get my LS harness all made up, what am I needing to do with my stock wiring in my truck. Does the LS harness just replace what's needed and the rest of the stock wiring (headlights etc) just remain in the truck and work fine? thanks for any insight I just never see this talked about.

[solidaxel]

Your L S will be a stand alone harness, with a switched 12VDC and a constant 12VDC

[mongocanfly]

Ditto to what solid says..the ls stands alone just be sure to ground everything ( motor to frame, body to frame, motor to body, of course battery to motor..) you can't have to many grounds, but on your truck side harness you will still need power as well so dont forget to hook that back up to. I used the big red wire from the hei for my switch on power, the original starter wire from the key went right back on the ls starter and the hot side wire from the starter went back up to the 2 pole connector on firewall above distributor and that should keep all your truck electrical working and that's where I picked up my constant power.

[Robznob11]

Yea your ls harness will have a battery hot, ign hot, ground, fuel pump,tac, tcc brake, and vss, if your lucky it may have e fans depending on who built it. The battery power should feed relays one for ls harness main, and one for fuel pump relay, you should have a minimum of 4 fuses to run your injectors and other . You can tie it in but it's best to Lear it stand alone less mess to chaise later.

[solidaxel]

Originally Posted by mongocanfly

Ditto to what solid says..the ls stands alone just be sure to ground everything ( motor to frame, body to frame, motor to body, of course battery to motor..) you can't have to many grounds, but on your truck side harness you will still need power as well so dont forget to hook that back up to. I used the big red wire from the hei for my switch on power, the original starter wire from the key went right back on the ls starter and the hot side wire from the starter went back up to the 2 pole connector on firewall above distributor and that should keep all your truck electrical working and that's where I picked up my constant power.

That is exactly where I tied in my Hot and Switched

Temp gauge to pass side head
Oil sender to by pass in LS
Starter to ing. switch, same location
Alt lead went to the Alt

It really is that a plug and play system !

[encasedmetal]

thanks so much everybody- this is exactly what I needed to know

[suburban99]

Here's a pic of my '62 under the hood. I kept the stock harness and just added what was needed for the LS to run. 4 fuses and 2 relays, diagnostic port, and the PCM of course.

[LongC'67]

Thanks for starting this. I'm curious myself. I'm to the point on my build where I'm asking the same questions. Just had my stand alone built by Modern Vintage in Indiana. I'll be following this for sure

[encasedmetal]

How are gauges like oil pressure and coolant temp tied in? Do you have to go aftermarket for gauges to read what the LS sensors are reading?

[suburban99]

I went with aftermarket because my 62 only had idiot lights. I just changed my fuel tank last week and have not hooked up the fuel gauge but I know it's a 90 ohm and the gauge is 30 ohm. I will probably use a potentiometer to correct.

[mongocanfly]

Mine had idiot lights to. I went with mechanical gauges also. The ls harness reads of the sensor on driver side head. I drilled and tapped the passenger side head for my temp gauge,, on the oil sender I used the autometer adapter to go from metric to standard npt and hooked my gauge to it.

[badherb]

although I have yet to accomplish my wiring for my LS in the 60 I will be using this guys site and his help for programming my ECM. He has a bunch of info that could be very useful.
http://lt1swap.com/2000harness.htm

[BR3W CITY]

^ Lt1swap is like a default resource for swap wiring. 70% of wiring questions can be solved with like 15minutes on the diagram sections over there.