1994 OBS GMT400 to LS Wiring

[@LT1SWAPCOM]

Not a very polished video, I've had this recorded for a few weeks and just have not had time to get it up. Life, work, kids, school stuff keeps me busy. Let me know your questions!

[@scottvandyke1272]

By the way, I love the video. I had to keep my VSS wires; mine is 4x4, and that was the only way I could figure out how to keep my original speedometer working. So I married the 2001 VSS wires to my 1994 wires.

[@jeremysmith2753]

Are you by chance going to film this as you install/incorporate both harnesses into the obs? That would be awesome if you are as you work and wiring diagrams and everything you do for the hot rod and car world is 2nd to none!!! You have helped so many car guys that it would be unbelievable!!! THANK YOU for everything you do as i for sure very much appreciate it!!

[@here_to_watch2115]

Good info, I appreciate the video.

[@mugsy_bo7174]

I kept the 2 pink power feed wires that went towards the transmission. In case i add some stuff later that requires [ 12v key on power ] and the orange wire that powered the ecm i used as 12v constant to power my OBD2 port

[@kylethedriver9360]

Thank you so much for this. This is the exact build I’m doing so it’ll be nice to reference this video when I start my swap.

[@halljam70]

Gray relay is for the 3rd center high brake light. Correction, it is related to the two other brake lights. I had cut the one of the wires (yellow) that ran from the black multi wire connector to that gray relay. I had power back feeding from it to my AC controls when brake pedal was depressed. Cutting took out the two lower brake lights but the cab mounted brake light worked. Repairing the cut wire and finding a ground wire I missed and now all the brake lights work and no back fed power is going to the AC controller.

[@charlesgarrett414]

Exact video I've been waiting for from you. I have a 93 that I sourcing info for. I have a 2002 ls harness along with a 94 harness I bought. Keep the updated videos coming

[@matthewdortch1326]

Awsome video. Thank you for all of the info you provide it is all very useful. I am doing a 94 swap currently and am at the wiring portion so this came out at the right time for me. Thanks again

[@07bluelbz]

Fixing to swap an 89 so this is quite helpful. I have an ebay harness on hand but i think im still going to use the donor ls harness.

[@jeremysmith2753]

I followed this video to the T and everything seems good except for my purple tcc brake wire. It stays hot all the time even with the brake pedal depressed. Ii have not figurex out why and was kiimda hoping that maybe you have run into this and maybe found the problem? And also have you had the chance to put the shematics and sfuff on your site? I just seen where you told 1 of the guys that commented on here you would have it on there very soon. Thanks for the awesome work man as we all sure do appreciate everything you do!!!!!

[@Stubbs21]

Will this video work with the 1994 5.7 tbi as well?

[@mugsy_bo7174]

Worked on my 94 5.7 tbi ext cab …did a gen 4 5.3 swap

[@dariusstubbs6125]

Greatly appreciated

[@MIKEKN0WSshorts]

This video came at the perfect time! I’m gearing up to do an LS swap on my 5speed manual 92 k1500 daily driver with a 4.8 from an 04 Yukon. I pulled everything from the Yukon myself so I have the computer and fuse box that was on it. Question is, do you use the fuse box from the donor vehicle or run an aftermarket fuse box? Looking forward to the tbi pinout, and thank you for all the info on your website!

[@scottvandyke1272]

I have a 1994 Yukon. I'm working on the bulkhead wiring diagram section where I get the alternator and temperature wires. I see green and brown wires, but should I pull them from the lower large loom?

[@brax10plays65]

What did you end up doing with the small gray box with the tcc wires going to it?

[@malcolmmok08]

Would you show which wore is the mil or check engine circuit so we can hook up the light on the dash?

[@LT1SWAPCOM]

check the page on the website in coming days. I have the pinout for the black connector near the factory ECM location that has the TACH, Check Engine Light, Brake Switch wires going through it. I will also be posting ECM pinouts for the TBI so you can identify the fuel pump control, check engine light outputs easier.

[@jarianbrass5021]

@@LT1SWAPCOMif I’m not mistaken the check engine light wire is brown

[@rodneyharris5606]

You service to the hod rod and swap community is 💯🍻💯🍻... Been looking at Lt1 swap for probably more than a decade