LS3 Engine Harness Length

[Lancaster Lad]

Sorry to bother you fine folks on your day off but I have a question on my engine harness.
Some background first. I am building a Roadster and know this is the Hot Rod section
I Figured there would be more LS people here. I have the connect n cruise 376/480 with
the 4l70e auto trans. I started to lay out the harness and everything fits fine but have about
2 feet extra wire for the computer and about 1 foot extra on the fuse box. If I leave the harness
as is the computer will end up by the headlights. The question is has any one shortened the
harness and if so which end. It would be easier to do the ends but most fit good, the other
option is to shorten the wires by the computer connector. That is a lot of connectors that could
be misplaced. I would never splice the wires but use new connector pins. I have the tools and
could find new pins but just don't want to mess with it. At the same time that is a lot of extra
cable to deal with and try to hide. There will be no room in the interior as I am going with AC
and an IDIDIT column similar to the Hot Rod.
I thought I read of someone cutting their harness but don't remember any details.
One way to do the computer end is to unwrap all the way to the oil pressure connector and with the
wires loose and more flexible shorten one wire at a time and plug it into the connector and when
finished rewrap the harness.
Thank you in advance for any and all help

Cecil

[AZREALTOR]

I have a 33 hotrod but it is not computer controlled. I do however have a 56 Chevy Pickup I put a computer controlled small block and 4L60 E in last year. I ended up with the same issue you are having. My harness was from Hotwire in Mena Arkansas and I have nothing but good things to say about them. Mine was too long but I put the computer under the seat so was able to just make a coil of the wires and lay them on the floor under the seat. In your case you might look at putting the computer under the passenger seat if you are using seat risers or maybe behind the waterfall. If none of that seems like an option you might be able to lay the wires along the juncture of the trans tunnel and the floor alongside the emergency brake and back to the computer. It would then be covered by the carpet. As you may be able to tell I would go to great lengths not to cut the wires but if you are capable of cutting them and re-pinning the connections that would be the cleanest. You may also be able to get a pre-fabbed harness extension and put the computer in the trunk. I'm sure you'll get more options but these are a couple I can think of.

[Lancaster Lad]

AZ thank you for a quick reply.
The seat thing will not work as the seats are as low as can go so I don't look at the top of the windshield.
Being this is a roadster they were not designed for autos so almost no room in the trans tunnel. Also
my exhaust will be down there no sidepipes. I may just put the computer up by the headlights. If you
had seen a GMPP harness would see how thick the cable is around 1 1/2 inches.
Again thank you for some ideas.

[HVACMAN]

I have the same 376/480 and 4L70E in my Hot Rod. I mounted the fuse box behind the firewall, the ECM over the pedal box and the TCM will mount to the tunnel under the console. The laptop port will be accessed in the glove box of the console. IMG_1183.JPGIMG_1205.JPGIMG_1206.JPG

[Lancaster Lad]

HVAC Thank you for the reply. The computer back routed toward the driver footbox seems possible. I really want
the fusebox easy to get to as I am no spring chicken and can't crawl under the dash anymore so might mount it near
pass footbox / fender. I plan to have some kind of console so the trans controller may fit behind it. I don't have the
ac evap box yet to see if there is enough room to route the cable as you did. When I get home I will check your possible
routing.
Thank you for the ideas.

Cecil

PS I also want to thank you for helping me spend my money. What I mean by that is the Lokar Sport Shifter.
I didn't know about it, I was just going to use a toggle switch to turn on manual mode. Lokar has also figured
the shifter throw to match the trans, I'm still trying to fab a bracket on the trans to match the C5 vette shifter
I have. THANKS A LOT!!!
I do follow the Hot Rod forum because of the LS3 tips, not many on the Roadster side.

[JimLev]

Lancaster Lad, I'm also using an LS3 and the 4L65e with a Lokar shifter.
Might be some useful info for you on my build thread, probably start at post 126.

https://thefactoryfiveforum.com/show...-s-Build/page4