Electrical Upgrade
by Morris "Texmo" Cox

We all face it with our old trucks -- that rat's nest of wires, complete with splices upon splices upon splices for who-knows-what kluge job or after-market add on that no longer is there. Yikes! It's a regular electron rodeo! If that's where you are, here's a good example of a complete re-wire. Yes, it IS do-able! It just requires patience, diligence and fortitude! With thanks to Richard "Truck26" Rosielle for helping us look over the draft of this document, here's Texmo to walk you through his journey towards gettin' all those wayward 'trons marching in formation and keeping everything happy, functional and... safe!

New Electrical Harness -- In your own living room!

         I’ve never written an official “Tech Tip” before so maybe we can just call this the results of my recent electrical adventure. I undertook this upgrade to change my 1963 C-10 LWB Fleet from an occasional weekend eccentricity into a truly reliable daily driver. The decision process to undertake a complete re-wire on the truck was the result of trying to figure out why my tail lights, cigarette lighter, fuel gauge, horn and radio wouldn’t work. In the process of trying to figure out the 43-year old wiring harness and multiple splices, loose wires and corrosion I figured out that I would save money, time and frustration by just scrapping the entire electrical system and starting over with stuff that I knew was good.

         Some of the things I found while tearing out the old harness included wires melted together, bare wires that had been stripped at some point in the past for a splice and wrapped with long deteriorated electrical tape, wires spliced into the harness that were tied to nothing on the other end, a button mounted underneath the dash to make the horn work because whoever had the steering wheel off last, re-assembled it wrong which probably led to a horn that was constantly blowing. So they just cut the wire coming out of the column and spliced in the button using the tried and true “twist wires together and wrap with black tape” method.

         What follows is my best effort to outline how I went about it, what parts I use, and the source of the parts. I’m sure that others have performed this upgrade using different methods, different parts, and different resources. But this worked out well for me so I thought it might be useful for others who have never re-wired a vehicle before. It might also be worthwhile to state what my automotive background is.

         I did receive some formal training 22 years ago, compliments of the US Marine Corps. Shortly after getting out of the Corps in 1988, life took over in the form of wife, kids, job, etc. and I was away from turning wrenches and focused on making a living. The acquisition of the ’63 in late 2005 was a refreshing return to busted knuckles and greasy finger nails. However, the mechanical lessons of my youth were only vague memories and I was a bit nervous when I started working on it.

         Now that I’ve given the status on the truck and my mechanical abilities, I should probably get on with it and describe the actual upgrade project.

Upgrade Summary:

• New 21 circuit wiring harness
• New 63 Amp internally regulated alternator
• HEI
• New heater blower motor
• New dash insert and Dolphin “fishless” gauges
• New defroster ducting (I know…it’s not electrical, but I was under the dash anyway)

Pre-Planning

         I knew that I wanted to end up with a solid electrical system, but wasn’t real sure how to go about it. I saw a post on The Stovebolt Page that led me to Alan Horvath’s website and the electrical work that he did to his ‘54 Chevy truck. I read every word and took notes. Alan did a great job of documenting his work and provided me with the confidence to jump into this job on my own. I sat down with a Big Chief tablet and a #2 pencil and started trying to sketch out what I wanted the electrical system to look like. This gave me a good idea what I DID NOT know and therefore needed to research. The resources that I used are listed below.

         Once I had a pretty good idea how to proceed, I sat down again with the Big Chief tablet and #2 pencil and sketched out a rough schematic of the engine bay to show where I wanted to mount everything. This involved several evenings after work in the garage leaning on the radiator support with a frosty adult beverage in one hand and lots of head scratching with the other. When I got stumped on how to set something up or where to put something, I would go inside and get on the computer to either do a little research or post a question on The Stovebolt Page forums. The schematic that I eventually came up with is attached to this little missive in the hope that someone may benefit from all of my head scratching and question asking.

Buying Parts

         When I had my schematic together and my research complete, I started getting parts together. I tried to replace parts as much as I could, but there were some of the connectors (i.e. the harness connector that hooks to the turn signal switch coming out of the steering column) that I couldn’t find a sources for so I salvaged them by carefully removing the connectors from the old harness, removing the crimped spade terminals from the inside, replacing terminals and re-inserting them into the connector. A list of parts and their source is listed below.

         Note: On the advice of Mark with Mad Electrical, I ordered the relay kit to get the tech book that comes in it and then ordered my additional relays from Parts Express where they are substantially cheaper. Mark is a great guy who, once you get him on the phone (he’s pretty busy), wants to know all about what you are doing with your ride…regardless if he is selling you anything or not. His advice was invaluable in getting this job done.

Where does all this go?

         OK, now I’ve got a living room full of parts (and one moderately perturbed spouse) that I need to make some sense of. Seeing everything on paper is one thing, but when it is all piled up in one place the thought runs through your mind …what was I thinking? I’ve got all this money sunk into this stuff and I’m not sure I can pull it off! Don’t freak out …it will all eventually come together.

         The first thing I did (I couldn’t resist) was take out that shiny new dash insert and mount the gauges in it. Talk about incentive to get on with the drudgery of wiring! Once I saw those gauges mounted in the insert, I couldn’t wait to get to a point where I could put them in the truck, but now it was time for more planning.

Plan your work ... Work your plan…

         I know that I seem to be harping on the planning phase of this operation, but I believe that it saved me countless hours of doing something and then re-doing it because I either did it wrong or put it in the wrong place. Once I’d had a look at the actual parts, I dug out the schematic that I put together and re-vamped it to match what I had on hand and to take into account what else I’d learned when I talked to various people during the order process.

The Work

         The first thing I did was take the wiring harness into the garage and lay it out on the floor next to the truck. This allowed me see how and where the various wires would run. Mine ended up in three main bundles: engine bay, dash, and rear of the truck.

         * The engine bay bundle went straight through the firewall on the driver’s side to hit the alternator, headlights, etc.

         * The dash bundle was divided into two sub-bundles: one for the gauges and dash switches, and one that went through the firewall and into the engine bay on the passenger side to hit the distributor, starter, etc.

         * The bundle going to the rear of the truck went through the firewall in the factory location on the driver’s side of the tranny hump and had three sub-bundles:

• One to the tranny for back up lights
• One to the fuel tank for sending unit and fuel pump
• One to the rear of the truck for lights

        The entire process was made easier by the fact that the harness I used was marked at regular intervals with imprinted labels that told me where the wire was going (i.e. Right Front High Beam, Left Rear Turn Signal, etc). Once I had the wiring harness split up and re-organized using small plastic tie wraps, I took it back into my parts storage facility (living room) and deposited it until it was needed.

         Once I had all of the old wiring removed, I started mounting the stuff under the hood (terminal blocks, relays, ground points, etc). This is a pretty straight forward exercise. The only thing that you should really keep in mind is to make your wire runs as short as possible for items that draw a lot of current (headlights, distributor, etc.).

         Now that I had everything mounted, I requisitioned the previously sorted out wiring harness from my storage facility and started installing it in the truck. My wife was so pleased that she actually helped put it in the truck! Installing the harness was simply a matter of routing the wires to the previously determined locations, putting loom on the bundles and tying everything down with plastic ties or insulated metal tie downs that are mounted using sheet metal screws.

         Note: All connections made while installing this harness should be crimped (butt connector, ring terminal, etc.), soldered, and then insulated using shrink tubing. Un-insulated, tinned connectors can either be purchased at your local electronics store or through Mad Electrical. I followed this practice throughout this project …I didn’t want to end up with the same problems that led me to start this project in the first place.

         Eventually, all of the wires found a home and were secured in place and I got my gauge panel wired. Now it was time to see how well I did. I connected the positive battery cable and grabbed my trusty multi-meter. With the meter set to read amperage, I connected one lead to the negative side of the battery and the other to the negative battery cable. Amazing! No current draw! This meant that, at least, I had managed to avoid any direct shorts or wiring anything to be permanently hot. It also meant that when I turned off the key, I wouldn’t have anything killing my battery.

         Finally, I connected the negative battery cable, held my breath and turned the key on. Everything appeared to be working -- lights, turn signals, horn, gauge lights (really cool!), cigarette lighter, wipers, etc.

         Now for the big test … the start up. Five minutes of grinding away on the starter and nothing. I had forgotten a ground wire connection on the relay going to my distributor. I made the final connection and tried again. With a belch of white smoke from all the extra gas in the intake from the first failed attempt it stumbled and started to run. There was never a sweeter sound than that stumbling, out of time, backfiring rumble! In a few minutes I had it timed, burned off the excess gas and had it purring like a kitten. Success!

A few random pointers…

• All connections in the harness should be crimped, soldered and insulated with heat shrink tubing.
• When organizing the harness, don’t forget to add ground wires where you need them. The wiring harness I used didn’t come with them already in place.
• Use terminal blocks to organize connections and provide a reliable power distribution point. I used three under the hood.
• Don’t rely on 40+ year old sheet metal to provide a good ground if you can help it. Use ground points that tie directly back to the battery via a dedicated ground wire. This is similar to a terminal block, but un-insulated. I used a bolt through the radiator support as my ground point under the hood, and a bolt through the firewall for all ground wires under the dash. I put ring terminals on the end of my ground wires and secured them to the ground point with a nut.
• Don’t forget to ground the block to the frame. Most older vehicles have somehow lost their ground strap some time in their checkered past. REPLACE IT! It’s also a good idea to run a ground strap from the frame to the bed since your rear lights are grounded to the sheet metal through their housings. An even better idea is to solder a ground wire to each housing and run it back to the frame. Whichever method you choose, do everything you can think of to ensure that everything is grounded. Bad grounds can make an electrical circuits do strange things.
• Unless you install a dedicated power circuit into the harness (hot and ground wires), install the charging circuit first, at least the “hot” wire from the alternator to the positive side of the battery. Ideally you would also run the dedicated ground wire from your ground point to the negative side of the battery as well. This is heavier wire and is easier to run and organize without any other wires in the truck.
• When you remove the old harness, don’t damage anything you don’t have to. You might need to salvage a connector or two. When I cut the harness loose from the wiper motor, blower motor, etc., I left three or four inches of wire attached to the connector just in case I had to splice that connector back into my new harness. When all was said and done, I had to salvage the connector for the ignition switch and the turn signal switch, but I did manage to change the crimped terminals to new ones that were crimped and soldered in place.
  
• Use new connectors if at all possible. The accessories in your truck may have some weird connector that is no longer readily available in which case you will have to salvage your current one and incorporate it into your new harness, but this is the only reason old wiring should be spliced into a new harness. If you do have to use an old connector, try and replace the crimp-on terminals inside the connector.
• This is a major improvement to your vehicle -- treat it as such. Resist the urge to take short cuts. The harness you are removing has likely lasted over 40 years because it was designed and installed in a professional manner, and there’s no reason to expect that this one won’t last just as long…unless you invalidate all of your hard work and research by allowing frustration or impatience to goad you into doing something stupid.
• If you do something wrong, fix it, right then, right there. If you don’t know how to do something, research it until you understand it.
• When you are sorting out your harness, make sure that you thoroughly understand where each wire comes from and goes to. The harness will likely come in pre-sorted bundles based on how the manufacturer thinks that they should go into the vehicle. Some of the wires in a given bundle may appear to go back to the fuse block, but instead the simply go to another bundle. There will also be wires in the harness that you might not ever need like power windows, power door locks, etc. Once you are SURE that you will never need them trace them back to the fuse block, cut them as close to block as possible and remove them from the harness.

A few pictures that may be helpful (or not)

• Driver's side radiator support
• Main power distribution terminal block, driver's side inner fender
• New connector installed for turn signals on hood
• Ground strap from block to frame
• Waytek Electrical Connectors
• 1963 Chevrolet C-10 Engine Bay Wiring Diagram
• Ignition Switch Wiring
• Headlight Switch
• Gauge Panel (back view)

       Be sure to check out our extensive Forums discussions -- from General Truck talk, Electrical Bay, Big Bolts, Panels and Burbs, Engine and Driveline, Paint and Body, Interiors, Tool Chest -- The Stovebolt Collective can help in your quest and walk you through the mire and magic of working with old iron. ~~ Editor.  

v. February 2007