Engine compartment wire routing

[MikeB]

For you guys who have installed a new wiring harness, I'd like to see photos of how you routed the wires for:

brake warning switch (on combo valve)
oil pressure sender
coolant temp sender
HEI power
HEI tach
electric choke
starter solenoid

I'm using the plastic "gutter" on top of the firewall, but can't decide where to drop down the wires.

Thanks.

[truckster]

Here's what I did. From left to right in the picture, the drops are: Starter solenoid, front engine harness - goes all the way to the temp sensor), HEI and oil pressure (I converted to electric), everything else. Since the brake warning wire kind of hangs out by itself, I used a couple of zip ties to attach it to the speedo cable.

[ThreeQuarter]

Mike, when I installed my AAW Classic Update kit, I dropped the brake sensor wire (tan) through the slot above the MC, I dropped the oil pressure sender wire, ignition, tach, and a ground wire (black wrap) down above my LH head, and then I ran the starter wire (purple) out the end of the gutter. My electric choke is powered by a jumper wire from the coil.

I later figured out the factory routing is to run all of them except the brake sensor out the end of the gutter (IIRC) and I wish I had done that. My "when I get around to it" list includes lengthening and re-routing those wires. I've stuffed some washer hoses in the gutter, too, but maybe they'll have to get booted in favor of the wiring.

[MikeB]

Originally Posted by truckster

Since the brake warning wire kind of hangs out by itself, I used a couple of zip ties to attach it to the speedo cable.

Thanks, Truckster. Yeah, there's no good way to route the brake warning wire.

My truck still has a bell crank and throttle rod, so I'm not sure what I'll run on that side. The linkage gets in the way of everything, including plug wires.

What kind of sleeving did you use? Looks nice. I also like what you've done with the washer pump hoses. Mine are just flopping around right now.

[MikeB]

Originally Posted by ThreeQuarter

I've stuffed some washer hoses in the gutter, too, but maybe they'll have to get booted in favor of the wiring.

I wish that gutter was deeper.

Very nice job on the wiring!

[A1971Blazer]

I'm eliminating the wiring gutters completely, I just don't like the look.
I have put holes in the core support so that all the wires will be routed up underneath.
I will extend the wires to the starter, temp sensor, and oil pressure all the way around to the back. Since I'm doing the LS1 swap, with all the wires associated with the engine harness, I want it all to look neat and clean..(hopefully)
I drilled a 3/8" pilot hole and worked in a Greenlee chassis punch to make a hole 1-1/8" thru the core support.

[truckster]

Originally Posted by MikeB

Thanks, Truckster. Yeah, there's no good way to route the brake warning wire.

My truck still has a bell crank and throttle rod, so I'm not sure what I'll run on that side. The linkage gets in the way of everything, including plug wires.

What kind of sleeving did you use? Looks nice. I also like what you've done with the washer pump hoses. Mine are just flopping around right now.

I used this split braided sleeve. It comes in different diameters. Mostly I used 3/8. I like it because you can run your wires just how you want them and install the sleeve afterwards. I put a mini cable tie every 12 to 18 inches just to keep it closed. Use a lighter to fuse the cut ends.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[MikeB]

Originally Posted by truckster

I used this split braided sleeve. It comes in different diameters. Mostly I used 3/8. I like it because you can run your wires just how you want them and install the sleeve afterwards. I put a mini cable tie every 12 to 18 inches just to keep it closed. Use a lighter to fuse the cut ends.

OK, that's what I'm using. I find it a challenge to melt the ends, so have used shrink tubing with the glue inside. However, you have to plan carefully, and even then you can't always use it on both ends of a segment.

I just ordered some 3M tape that fuses to itself and won't unravel like regular electrical tape, so we'll see how that works.

[MikeB]

Originally Posted by A1971Blazer

I'm eliminating the wiring gutters completely, I just don't like the look. I have put holes in the core support so that all the wires will be routed up underneath.

That's a beautiful truck. It deserves that bit of detailing!

If mine was apart like yours, it would be a lot easier to do the wiring. I'm 6' 2" tall and still have a hard time reaching the middle of the firewall. I wired a friend's 37 Chevy several years ago before its fenders and "doghouse" had been installed. That was easy peezy.

[Rickysnickers]

Originally Posted by MikeB

OK, that's what I'm using. I find it a challenge to melt the ends, so have used shrink tubing with the glue inside. However, you have to plan carefully, and even then you can't always use it on both ends of a segment.

I just ordered some 3M tape that fuses to itself and won't unravel like regular electrical tape, so we'll see how that works.

You can also try Tesa tape, https://www.amazon.com/s?k=tesa+tape...sl_noldw0q8f_e . I've used it on some small wiring projects on my side by side. It works really well.

[72SB]

Originally Posted by MikeB

Thanks, Truckster. Yeah, there's no good way to route the brake warning wire.

Originally Posted by ThreeQuarter

I later figured out the factory routing is to run all of them except the brake sensor out the end of the gutter (IIRC) and I wish I had done that. .

While I just removed all the old, falling off, tape, I just used new electrical tape to wrap it. When I did my manual to power brake conversion, I added length to the stock brown wire and spliced in the brake warning pigtail to it and ran that as discussed towards DS and zip tied it to the bulkhead to cowl harness that was there. I did use some split loom on that single wire

When I got the truck the EVAP vacuum lines and PCV hose were just randomly strung across the engine bay so I just ran new vac hose to clean up the engine bay to clean up everything

BTW, if using split loom, don't use that stuff you get at auto part stores. Its not meant for engine bay (heat). Grey stripe is heat resistant and blue is flame resistant. I buy 100' rolls in various sizes in both grey and blue stripe and use it on many wire clean up or additions on all my hobby cars. Its fairly cheap from online sources

[LS short box]

On my 69 C10 project I used a generic Painless 21 circuit wiring and tried to hide as many wires as I could. The front headlight harness I ran down the left frame rail and then inside the upper radiator support. I didn't have washer hoses to deal with. Other wires routed behind the engine out of site.
I too would only use the braided wire covering. I get it from Summit.

[MikeB]

Originally Posted by Rickysnickers

You can also try Tesa tape,

Funny, but that's actually what I ordered! I can't remember if the memory is the first or second thing to go!

That stuff is really nice. I did some experimenting today and the adhesive seems to "stay stuck" even after I hit it with a heat gun. The standard electrical tape, even 3M, gets all gooey, starts to come loose, and leaves a big mess if you ever have to remove it, even if you use it in a cool place, like under the dash.

[cornerstone]

I'm doing the same thing currently, deciding where each of these wires will go. I have smoothed my firewall and eliminated the wiring gutter as well so I suppose I'll need to lengthen some of the wires and find creative ways to keep them out of sight. Thanks to those who have added pictures of engine bay wiring.

[CKfan]

Originally Posted by LS short box

On my 69 C10 project I used a generic Painless 21 circuit wiring and tried to hide as many wires as I could. The front headlight harness I ran down the left frame rail and then inside the upper radiator support. I didn't have washer hoses to deal with. Other wires routed behind the engine out of site.
I too would only use the braided wire covering. I get it from Summit.

That looks really, really nice under there. Well done!

[MikeB]

Originally Posted by cornerstone

I have smoothed my firewall and eliminated the wiring gutter as well so I suppose I'll need to lengthen some of the wires and find creative ways to keep them out of sight.

If you are looking at kits, the AAW Classic Update kit gives you lots of extra length for most of the wires, including all the front lighting and engine wires. I just now measured my starter solenoid wire. It is literally 6 ft longer than required for stock routing!

If you end up having to buy lengths of wire, be sure to use wire designed for high temps, which are rated TXL, GXL, and/or SXL. Their "cross linked" insulation also resists abrasion. There are lots of good sources for them in various lengths.

[Rickysnickers]

Originally Posted by MikeB

Funny, but that's actually what I ordered! I can't remember if the memory is the first or second thing to go!

That stuff is really nice. I did some experimenting today and the adhesive seems to "stay stuck" even after I hit it with a heat gun. The standard electrical tape, even 3M, gets all gooey, starts to come loose, and leaves a big mess if you ever have to remove it, even if you use it in a cool place, like under the dash.

Yep, it works well.

[MikeB]

Making progress. Decided to run the engine wires all the way to the passenger side, then across the manifold behind the carb.