When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I had to decide which task to attack next, so I figured I’d get to work on the biggest and worst thing on my list…..wiring…….
I had earlier done a successful test run on this drivetrain with the stand alone harness I had made by modifying the original harness that came with the motor/tranny. I still needed to get things ready for final installation of the wiring system, and this consisted of carefully identifying every last wire that left the harness to go into the cab, making detailed notes to assist in future trouble shooting, and finally extending all the wires that were clearly too short.
One of the main features of an LS swap that is so often touted on-line is the claim that a stand alone harness only needs 3 wires to run things. Technically this is true. It will run with 3 wires, but there’s more stuff that you would definitely want to keep. By the time I had finished things up, I had 22 wires going out of the harness, and once I do the main cab/body wiring I will have a bunch more that will be routed back into the engine harness.
Here’s just some of the wires coming out of my “3 wire stand alone harness”:
Now to be fair, my drivetrain is from a 2006 truck, and it's more complicated than the previous years due to the addition of drive-by-wire and the Generator Battery Control Module. I won't bother detailing what the 22 wires do, as it’s specific to certain years of LS engines (unless it’s of interest on this forum, but I kinda doubt it!). At this point I had a pretty good idea of what I needed to do with all those engine harness wires, and the next step would be adding the body harness (some of which would come and join the engine harness).
I had hoped to do a bigger wiring post, but I have to stop here to fire up the tractor and start blowing snow again.
One of the depressing things about wiring is that instead of things looking better as you progress, they look worse and worse for a while. You start off with a nice shiny box of neatly coiled wires like this:
And then you start to route bundles to the general area where they go, and stuff starts to look sloppier and sloppier:
Just when it’s looking like a total disaster, you start to finally route some bundles to where they need to be:
However just when things start to look good and you feel like you are making progress, you find stuff that you either forgot about, or that just doesn’t fit. When I plugged in the connector that held all the turn signal wiring, I discovered that it was directly in the path of the brake pedal. The connector is affixed to the GM column by a steel bracket that is spot welded to the column. Here’s the column, and here’s my first attempt to drill out the spot welds:
When it refused to budge I looked closer and discovered another 3 spot welds I had missed. That’s 9 spot welds to affix a bracket that holds a mickey mouse plastic clip! I then shifted the bracket (which now looked like swiss cheese) over a bit so that the brake pedal would clear it and welded it in place (with 4 welds, not 9!)
I also realized that I had forgotten all about the brake switch, so I fabbed up a bracket to install it:
The wiring job is going slowly, just like I figured it would.
The wiring continues, particularly the stuff that doesn’t fit/work! I had worked my way into the dash area and was going to tackle the instrument panel. I had purchased one of those custom 5 gauge panels, and I had splurged on a set of Autometer gauges. Here’s the stuff I’m talking about:
I wanted to do a test fit into the dash, so I installed the voltmeter in the upper right corner as this is the only spot with potential fitment issues. I ran into my first problem right there. I was having a hard time getting the lightbulb socket to plug into the gauge, and when I looked closer I saw why. There was not enough space on the gauge to do it. The bulb socket hits the nut for the wiring:
I had to take about 1/16 inch off the side of the bulb socket to create enough space to be able to install it:
Keep in mind that this was the bulb socket that came with the gauge. I was not terribly impressed.
This was however minor stuff compared to the next problem. When I did a test fit of the gauge panel into the dash, I found that the voltmeter pressed up against the wiper motor, preventing installation. The design of the gauge fastening system creates an overall package that is very deep, despite the compact size of the actual gauge itself.
I wasn’t expecting the interference with the wiper, but to be fair it's a non-original electric wiper that I installed myself.
Out of idle curiosity I strolled over to my son’s 1950 F3 and tried a test fit there, and it still didn’t work. The gauge pressed against the original vacuum wiper preventing installation. I was a bit surprised at this point, as I have seen a zillion of those gauge panels in Monkeyfaces at various shows.
The fix wasn’t difficult, but it did burn off a number of hours (as usual!). My old mounting bracket had left the wiper motor just a bit too low, so into the scrap bin it went, leaving me back at square one. Here’s the original mounting point, with the addition of a bolt I added that you can see on the right side (the bolt will hold one side of the motor soon):
After removing the windshield air vent, here is Mounting Plate 2.0 being test fitted, as well as being scribed to mark the hole for that bolt in the previous picture.
Using a template, I drilled a hole for the mounting bolt, as well as holes to match wherever there were bumps on the face of the motor. These “bumps” were just small screws, but the holes I made for them did 2 things. They helped move the motor forwards, buying me more clearance from the gauges, and they helped anchor the motor against the mounting plate.
A test fit:
Then re-installation of the vent and another test fit only to discover……………….still no dice! Mounting Plate 2.0 did move the motor forwards (success) but the new angle brought it upwards (which did create a nice clearance gap from the gauges), but now put the motor up against the windshield vent. The vent merely needed a little bit of clearance:
And…success! I forgot to take a picture, but you get the idea. While I had the dash empty and had lots of room to work I decided to finish the wiper system once and for all. I never want to fool around with another Monkeyface wiper again. It truly sucks working up inside the dash. I'll detail the rest of the work later as this post is getting kinda long winded.
Continuing on with that annoying electric wiper…….
I grabbed a short chunk of some thick rubber hose and slid it over the wiper shaft. This was actually used earlier to help me centre the shaft in the cowl panel hole during the creation of Mounting Plate 2.0.
The bezel, rubber seal/washer and retaining cup were test fitted:
And from this test fit you can see that the inner and outer wiper shafts are way too long (they come that way on purpose due to the universal fit design). I merely had to shorten them up:
And then drill a hole for the retaining screw that keeps the knurled fitting tight onto the wiper shaft. The knurled fitting is what the wiper arm actually sits on. The big outer shaft with the threads merely holds the wiper down on the cowl panel.
The whole mess was reinstalled and tightened up. That rubber hose was left in place as it keeps the shaft centred in the cowl hole. Without it the escutcheon wants to slide up the curve of the cowl when things get tightened down. A rubber water seal was added as well:
And finally after a ton of fooling around, SUCCESS!
The wiring continues………Finally I’m now doing some actual wiring which is interesting and kinda fun. I started with something simple, the panel I made for warning lights and Wiper & Cruise Control switches:
Then I switched over to the main instrument panel. I switched over to weatherpacks as it was the only connector type I had on hand that could handle a dozen input wires:
Here’s the panel with just the gauges. It starts off really simple looking:
But it sure starts to get busy towards the end:
Of course nothing says “original 50’s technology” like an OBD2 port! (The pic makes it look kinda obvious, but it's actually hidden from view)
Making progress under the dash. Still needs proper routing and taping, but not until I debug things:
There are no 2 identical connectors anywhere under the dash, so that its impossible to plug the wrong things together. Other than the OBD2 port, everything has its own connector. This way if I have a problem (for example a gauge issue), I can just unplug the works and yank it out for bench testing.
I was now at the point where I had pretty much done what I could inside the cab, but I still had a mess to deal with under the hood. That’s as far as I got.
Continuing on with the wiring, I’m still spending a ton of time on little stuff that slows me down. I had shifted to doing the front half of the truck (forward of the firewall), and I had to run wires through the firewall for the TAC module (my throttle is drive-by-wire). Of course the plugs are large, so in order to get the wires through the firewall I had to de-pin one plug. I’d grabbed a cheapo set of de-pinning tools a couple of years back, and it has come in very handy on many occasions. This weatherpack connector was a case in point. Here’s a few shots of me disassembling the connector and then doing a pass-thru of the firewall with a nice, small hole:
I had to order some stuff to do underhood relays, so while waiting for those supplies I dealt with lights for a bit. My truck has the single filament bulb in each parking light assembly but those had to go as I am adding signal lights.
Here is the parking light housing with the old light socket that had to go. In the upper left you can see the new dual filament bulb sockets:
The sockets are pressed into place, so removal was just a matter of finding a long socket that just fit over the old light socket……..
….then flipping it upside down…..
….then finding a socket that just fit over the old light socket, and tapping it with a hammer….
The new socket installation was just the same sorta stuff, however I found that the new ones were just a hair loose, so some gentle swaging of the lip of the housing was required to ensure a nice, tight fit:
I also added a grommet to each new socket, as the wires exit through a nice sharp steel hole in an area that vibrates constantly (what could possibly go wrong there?).
While waiting for some electrical terminals to arrive I killed a little time dealing with tail lights.
I tried to install a pair I had ordered, but discovered that they wouldn’t fit due to the farmer-fix angle brackets that had been welded to the rear of my truck (which I am keeping). I made a template of the original bracket based on what I had on hand (a badly bent bracket from my truck, and another badly bent bracket from my son’s truck-what did people do to these trucks back in the 50’s????). Using the template, I plasma cut a fresh pair of brackets and tossed things together
While dealing with the tail lights I dealt with a little wiring as well. I wanted to be able to remove the box as easily as possible, so I added some weatherpack connectors for the rear lights:
This was a fairly short update as I got sidetracked by my son and the 1950 F68 he brought into my shop last September. I told him that I’d give him advice and show him how to do things (he’s a newbie at car stuff) but it was so much fun working with him that I ended up doing all kinds of stuff and ignoring my own build. Well worth it for the quality time spent with my kid. I’m thinking of starting a 2nd build thread to cover what we are doing on that 1 ton truck of his.
Thanks Ingo. Wiring is turning out to be extremely interesting and actually quite fun. It sure beats fighting with aftermarket parts that don’t fit!
I finished what I could do with the tail lights for now as I still need to come up with reverse lights. Reverse lights are actually a big deal where I live as I don’t have houses and streetlights around me, so unless we have a good moon it's pitch black at night. In the meantime I shifted to the front clip where I still had a ton of wires to deal with.
I had to run 4 relays up front to cover:
-High Beams
-Low Beams
-Rad Fan
-Starter Solenoid
I picked up a cheapo Amazon relay/fuse box to use up front and got to work. I had bought a prewired one:
At first glance I was impressed as the wires were extremely heavy (a rarity for Amazon/China stuff), but then it occurred to me that for debugging purposes it would be a total pain to have wires changing colours. Nothing can screw me up faster than that, so I yanked out any wire whose colour didn’t match mine (most of them!) and fed the box directly from my harness:
My wiring kit (a universal Painless kit) came wired for headlights that were powered directly from the headlight switch, but I wanted very bright lights due to the lack of lighting around here, and as the incredible number of critters I see after dark. For this reason I added the relays to operate headlights. It was pleasantly simple to do, I just cut the high and low beam wires and routed them into the relay box to be used as the trigger wires and then crimped 2 wires to each output terminal (each wire feeds one bulb up front):
My lights should be plenty bright, as each bulb is supplied by only a few feet of wire as the relay box is extremely close to them. It should also keep my headlamp switch nice and cool (I’ve had ones in the past that got awful hot).
The starter solenoid also needed a relay according to the instructions provided by Painless. I used the existing neutral safety switch that is mounted on the 4l60e transmission, and apparently these switches have a short life expectancy if the full starter solenoid current is run through them.
The radiator fan also needed a relay due to its current draw. In this case the relay is triggered by the ECU which grounds the circuit (the opposite of the other 3 relays).
With the relay box wired up, I switched to the very front of the truck to finish off the wiring for lights, horn, etc. You can see that I had the front clip off, as it would be murder trying to work in those tight spots with the truck fully assembled:
I’m trying to make front clip removal easy for any future maintenance/repairs, so while the relay box is mounted on the inner fender it can easily be removed by accessing 2 bolts in the wheelwell. The same goes for my ECU and TAC module boxes. With the removal of 6 bolts, all wiring can stay with the engine. The wiring that will feed the front clip will be able to be disconnected with just a pair of weatherpack connectors. Here’s the bulk of the front clip wiring, just waiting for the addition of weatherpacks (to be done when the clip is on so that the lengths work out):
AC wires are tucked away for if/when I do that:
At this point I have made some great progress in wiring things up.
Next comes the battery wires, as well as the heavy wires to feed the alternator, fuse box and front relay box.
The wiring continues……..The actual wiring (routing wires, making connectors, etc) moves along at a good pace, but anything involving parts from the aftermarket screws me up, every single time……
My front wiring needed headlight sockets, which was just a matter of crimping the special connectors onto the wires and adding protective tape/loom:
I then switched over to the engine side of things as I can’t do the final weatherpacks that connect the front clip to the harness until the front clip is back on (I risk accidentally making things either too short or too long).
When I ordered my gauges I also ordered the kit that has the adapters needed to mount the gauges to an LS engine. LS engines have ports on both heads that can be used for the temp sender. The sender is removed with a torx bit. Most torx sets come with fairly standard sizes which include T50 and T55. Naturally GM had to use a T52 to make sure that no normal person would have one on hand. Thankfully the plugs in the ports are coated with something to prevent seizing, and I was able to use a T50 to remove the plug. The adapter and a new sender that comes with the installation kit was then tossed in:
The factory oil pressure sender is not required by the LS engine’s ECU, and it is located at the top rear of the block. Installing the aftermarket oil sender was simply a matter of first removing the old sender and putting in the new adapter:
And then threading the new sender into the adapter……….oh wait, I’m dealing with the aftermarket……..what’s wrong with this picture?
Yup, you guessed it. Before that sender can be turned down enough to seal it, it smacks right on top of the rear valley pan bolt. Keep in mind that every LS engine has that same bolt right there, and the kit came from the same manufacturer that made the gauges and is specifically designed to fit their gauges and their sender to this engine. When I sent a pic of this to their customer support, they suggested a remote mount kit to solve my problem. They also provided a handy link to such a kit that they just happen to sell. I considered this recommendation for 0.00001 seconds before deciding against it and instead I simply added a 2nd ⅛ NPT female to male adapter. This raised the oil pressure sender high enough over the valley pan bolt to allow it to be firmly screwed down into place.
I returned to wiring and continued on with the heavier gauge stuff. Based on a thread I read on this site, I had ordered up a hammer lug crimper a while back. I had never done heavy gauge wiring before and I gotta say that this little gizmo is fun to use.
I started with some lighter stuff (alternator and relay/fuse box feeds) and got to work:
The end result seemed pretty good to me. That protective coating that you see on the wire came off of a giant roll of wire loom that I had on hand. It’s the “chinese finger trap” type that can cover a decent range of wire sizes and is quite tough. I got it years ago at some suburban auction where nobody in the crowd recognized what it was and I walked away with it for just a few dollars.
I was so tickled with the results that I finally got at the battery cables (a job I dreaded as it was going to be 99 percent crawling around under my truck). I had predrilled and tapped holes for the wire clips along the route but had left a few areas without holes as I wasn’t sure where the wires would emerge to attach to the engine. Of course now most things are in place so getting my drill into some spots had gotten impossible. As usual my “wiring work” involved a welder and a grinder. I whipped up the required weld-on tabs……..
……and zapped them in place (the mig torch can reach into some pretty tight spots). I used the hammer crimper to add ends for the starter and the engine block ground bolt:
I then started to feed each wire along its route, adding a split loom protective cover as I went. It was a treat to not have to worry about measuring anything, I just pulled the 2 gauge wire off a big spool of the stuff that I had on hand:
I left enough spare wire sticking up through the bed to be able to deal with the battery ends later. That was it for now.
Hermit, I noticed you have 3 springs in your headlight bucket.
I know there are places for 3 springs but originally they only had 2. When I rebuilt my truck in 1999 I had several buckets to choose from so I had lots of springs so I put 3 springs in each bucket. This past fall I tried to adjust my headlights. One of the captured nuts for the adjusting screw broke off. I was getting help from Ken Effietrucker and he noticed it. Long story short I got the nut in place and went with 2 springs, one for horizontal movement and one for vertical movement.
I don't know if this is your left or right headlight . For your right (driver's side) one spring should be at 9 o'clock and one at 12 noon.
Matter of fact Ken showed me a picture of a reproduction headlight bucket that had only one spring. I don't know why and I don't know how they properly adjust the headlight
