55.2-59 Rear Wire Harness Routing

[57FleetsideC4]

Hi All, My project is almost all in paint and plan on putting it together over the upcoming winter. I will have a bunch of basic question as this truck was apart when I got it. Looking ahead to the wiring how was the front to back wiring run or where is the best place to exit the cab? Thank You Steve

[Hcb3200]

Mine goes out the provided holes behind the dash. Down against the fire wall and into the inside of the frame rail all the way back. Then across the rear to passenger side.

[dsraven]

are you building to look stock? if so, download a copy of the assembly manual that tells how it was all put together and held in place etc. free download at trifive site. google 55-59 chevrolet truck factory assembly manual and click on the trifive site for the freebee. download to a stick or something for future reference

[57FleetsideC4]

Originally Posted by Hcb3200

Mine goes out the provided holes behind the dash. Down against the fire wall and into the inside of the frame rail all the way back. Then across the rear to passenger side.

Thank You, I figured it went out and down the firewall. This isn't stock so just got to get the wires back there. Steve

[57FleetsideC4]

Originally Posted by dsraven

are you building to look stock? if so, download a copy of the assembly manual that tells how it was all put together and held in place etc. free download at trifive site. google 55-59 chevrolet truck factory assembly manual and click on the trifive site for the freebee. download to a stick or something for future reference

This is not stock look. I have downloaded that manual and will look more into that. Thank You Steve

[dsraven]

if you have plugged the holes in the firewall you could also think about going through the firewall down lower or the floor. that way there is less clutter under the hood. I have used something that looks like an extension cord to run the required wires to the rear on some industrial applications. it is smooth on the outside and has a fairly good neoprene rubber casing.it would be available from a trailer or trucking supply place.semi trucks have a 7 wire cord if required. I would run it to a sealed junction box at the rear and then branch out from there to the lights. I use the rubber coated bolt on clamps to tie the wire to the frame etc
https://www.grote.com/electrical-con...cable/82-5606/
https://www.cabletiesandmore.ca/cabl...insulated-zinc

[mr48chev]

Good quality trailer wire that is correctly color coded works great for the rear lights if your wiring kit doesn't have rear light wires in it.

I'd get some Adel clamps to hold the wire harness going to the back spacing them what ever I felt kept the wires or harness neat and orderly.

This isn't the one but i bought one of the trailer wire junction boxes for mdy 77 flatbed to clean up the rats nest of wiring back there.

At one time the truck belonged to a roofing contractor and was used to haul old roofing to the dump. They wired the taillights with a section of the yellow extension cords that a lot of contractors use and some SO cord. I actually cleaned it up a lot one night when I was towing my boat back from the coast and didn't have lights when I checked at North Bend.

[_Ogre]

i wanted a smooth firewall with minimal exposed anything. i mounted the ezwire panel just above the crease in the floorpan and exited the rear wires down below the crease. 2 pics without dash fascia and with dash fascia. the front harness exits on the right next to the heater hoses, ezwire harness was long enough to reach the left headlight and turn signal. i'm tall with big feet, 36,000 miles and 14 years i've never had an issue with the wiring.

[57FleetsideC4]

Originally Posted by dsraven

if you have plugged the holes in the firewall you could also think about going through the firewall down lower or the floor. that way there is less clutter under the hood. I have used something that looks like an extension cord to run the required wires to the rear on some industrial applications. it is smooth on the outside and has a fairly good neoprene rubber casing.it would be available from a trailer or trucking supply place.semi trucks have a 7 wire cord if required. I would run it to a sealed junction box at the rear and then branch out from there to the lights. I use the rubber coated bolt on clamps to tie the wire to the frame etc
https://www.grote.com/electrical-con...cable/82-5606/
https://www.cabletiesandmore.ca/cabl...insulated-zinc

Originally Posted by mr48chev

Good quality trailer wire that is correctly color coded works great for the rear lights if your wiring kit doesn't have rear light wires in it.

I'd get some Adel clamps to hold the wire harness going to the back spacing them what ever I felt kept the wires or harness neat and orderly.

This isn't the one but i bought one of the trailer wire junction boxes for mdy 77 flatbed to clean up the rats nest of wiring back there.

At one time the truck belonged to a roofing contractor and was used to haul old roofing to the dump. They wired the taillights with a section of the yellow extension cords that a lot of contractors use and some SO cord. I actually cleaned it up a lot one night when I was towing my boat back from the coast and didn't have lights when I checked at North Bend.

Originally Posted by _Ogre

i wanted a smooth firewall with minimal exposed anything. i mounted the ezwire panel just above the crease in the floorpan and exited the rear wires down below the crease. 2 pics without dash fascia and with dash fascia. the front harness exits on the right next to the heater hoses, ezwire harness was long enough to reach the left headlight and turn signal. i'm tall with big feet, 36,000 miles and 14 years i've never had an issue with the wiring.

Thanks for the suggestions, guys. I got a universal wiring harness with the truck and want to use it. Just was looking for the best or where the wires went originally. I don't mind seeing the wires just as long as they are neatly routed. This will be the first vehicle I have wired from scratch so looking for pointers and want to keep it as simple as possible. Thanks Steve

[dsraven]

Insulate harness with a rubber grommet anywhere it goes through a panel etc
Use wire loom on any exposed harness
Use clamps to keep harness retained tightly to frame etc
Use a non insulated crimp connector with double wall shrink tube whenever a connection is needed
Try to stagger multiple connections so as not to have a lump in the harness
Use a junction box where wiring terminates at the rear and splits off to tail lights etc.
A flat trailer plug connector from the box wiring and a matching end connecting to the junction box makes box removal easy later. Or simply remove the cover from the junction box when needed
Industrial electrical connections have a compression style fitting that can be used on a junction box and then when wiring is passed through the compression part can be tightened up to seal weather out
Try to use a sealed beam sort of light if possible that has a plug in rather than wiring up to a light socket. They are more reliable for shock absorption and less finicky as far as actual connection to the bulb

[57FleetsideC4]

Originally Posted by dsraven

Insulate harness with a rubber grommet anywhere it goes through a panel etc
Use wire loom on any exposed harness
Use clamps to keep harness retained tightly to frame etc
Use a non insulated crimp connector with double wall shrink tube whenever a connection is needed
Try to stagger multiple connections so as not to have a lump in the harness
Use a junction box where wiring terminates at the rear and splits off to tail lights etc.
A flat trailer plug connector from the box wiring and a matching end connecting to the junction box makes box removal easy later. Or simply remove the cover from the junction box when needed
Industrial electrical connections have a compression style fitting that can be used on a junction box and then when wiring is passed through the compression part can be tightened up to seal weather out
Try to use a sealed beam sort of light if possible that has a plug in rather than wiring up to a light socket. They are more reliable for shock absorption and less finicky as far as actual connection to the bulb

Thank You for all the tips on wiring. I will keep all of these in mind as I go through this process in the coming months. I am still a little leary of the harness that came with the truck. I have a decent schematic that came with it but have no idea who made it or the quality of it. Steve

[dsraven]

If doing any crimp connectors invest in a good stripper and crimped. Not necessarily a stripper and crimped in one tool. Klein makes a good crimped that is just a cutter and crimper.

[57FleetsideC4]

Originally Posted by dsraven

If doing any crimp connectors invest in a good stripper and crimped. Not necessarily a stripper and crimped in one tool. Klein makes a good crimped that is just a cutter and crimper.

I have purchased a nice set of crimpers and strippers that seem to work well. Another thing I will have to do is blend the LS harness with the truck harness. It will all work out I just have to take my time which I will have all winter to complete. I would like for this truck to be burning gas by spring. Steve

[Hcb3200]

I highly recommend leaving extra at the ends and a loop behind dash.
When I rewired mine I ended up having to move somethings around and having the extra saved me a lot of hassle. Once the project truck is “Done”. Lol you can always clean up any extra.

[dsraven]

great idea, I forgot to mention that. I always leave enough wire behind stuff to pull the part out far enough to reach behind and unplug whatever the thing is, dash cluster, radio unit, light etc etc.

[leegreen]

>Use a non insulated crimp connector with double wall shrink tube whenever a connection is needed<

I respectfully disagree. I solder every single connector after crimping then put heat shrink on it. I also arrange all wires so they are supported / strain relieved within a few inches of the connections.

The only way a soldered joint in typical automotive wire will fail is if you create a stress point where the solder ends - the soldered wire is stiffer than the un soldered so if it flexes it is likely to break off right at the solder. But if your wire flexes that much it is going to break eventually anyway.

If you are using weatherproof fittings with built in strain relief like modern OEM stuff then maybe crimping is OK, but you need the proper tool / crimp die for every size you do to get good results.

[dsraven]

totally agree LG, but most guys are not gonna sodlder or will usually apply too much heat and solder so the solder runs down the wire and makes a long stiff spot that will fail. I gave my alternative that most guys are gonna do because it is faster and also because they don't wanna screw up the solder thing. yup, a weatherpak or a metripack connector would be great but, again, not for everybody. the crimp connectors are what is readily available so thats what most guys are prolly gonna use. I do admire the soldered joints and have seen some really nice ones. I have seen some wierd ones too but they still worked.
at the heavy duty truck shop I used to work at the truck drivers would try their hand at wiring in lights or odd little things in the leased trucks. we spent many hours repairing odd wiring or burnt up stuff. finally the management made it clear that any add on stuff would be installed by the shop when the unit came in for the next service, just bring the add on and show where they wanted it, or, if the driver really wanted something bad, they could make an appointment and have just that item installed.

[mr48chev]

The solder or not solder thing has been argued around for the past 50 years that I have been paying attention. That should be personal choice an not feeling that you were hounded into doing it.

Using qualiy crimpers correctly an using the correct size for the terminal is important though. Plus some of these newer terminals that are a bit different design use special crimpers. I've got who knows how many different crimpers if I dig around in all the tool boxes Trunks, under the truck seat and in both boats. My favorites for general use are the Kleins that I have had for 30 years. They are usually the ones that go in my fix it on the side of the road bag when I travel.

[leegreen]

yeah, crimp and solder and insulate and strain relief

At least when you are building something. I'll cut some slack for roadside repairs.

[57FleetsideC4]

Thanks Lots of great ideas on wiring. I will leave enough wire if I need to service later. I personally like the crimp and heat to seal connectors they have always worked good for me. Steve