I thought now would be a good time to start a good tech thread. I just finished rewiring my crew, and there have been a bunch of electrical threads lately, so it seems like a good time to do a thread before I forget everything.
First, knowledge is power. Fordification has a bunch of really great schematics here: 1973-1979 Ford Truck Wiring Diagrams & Schematics - FORDification.net Print your year and get to know it intimately
Next, invest in some good equipment. I found that the 3M Super 33 tape

and Harbor Freight's Marine Heat Shrink

are really good. Skip the dollar store stuff and get quality stuff
Next, invest in a soldering setup. Crimp connectors are garbage. I made this little gizmo out of clothes pins and plywood to help with soldering

It is light enough you can use it to help solder in the vehicle if you have to.

Now that you are somewhat armed, where to start? I would advocate getting a spare junkyard harness. Why? Spare parts, or for rebuilding while the vehicle is running. I would also consider getting the one you want. For example, newer ones have more circuits. Also gauges and idiot lights are NOT interchangeable. If you want factory gauges buy a later harness with gauges. Also, I have found that for repair, pulling entire factory runs where possible is better than splicing. A spare harness can help with that.
Now for some random tech. I wanted to upgrade my truck with extra stuff. First, I wanted extra cigarette lighters. I put one in the top of the dash, and an extra one in the front.




I also put in under dash courtesy lights

To do this, it is fairly easy to connect to the factory harness. For the lighters, there is a constant hot

Here it is with a bullet connector installed

I did this by making an all-in-one harness for all the lighters. It is all factory colors (green/yellow) except for the lead that came with the extra lighter. This helps to reduce confusion when looking under the dash.

For the grounds, I pulled the spare ground harness out of the extra harness. These are really good because they have 6 or7 leads all joined together. The barrel looks like this, but the wires are all black:

Here's my grounding harness

Installed

It uses one ring for the factory ground point, but neatly grounds everything else.
On a related note, I used the gray connector to ground my stereo, and heat shrunk all my crimped connectors on to the harness

I used the cigarette lighter factory plug for constant hot, and the yellow one for keyed. Here's a picture of the keyed hot plug. It's sort of behind the instruments.

I also beefed up the stereo mount bracket

One thing I didn't make/modify is my headlight wiring. I bought one from LMC

Wyckedcombo made one, but for the money I couldn't make one, so I bought it.
Finally, one of the best things is that I have a box of factory wires with terminals for other things.

Hopefully this will help get some people started. Wiring isn't that hard, but is somewhat tedious. Take your time and do a good job and you can have a reliable vehicle for another 30 years

 

subscribing now Im planning to install a Painless harness into my 76 f250 and will want/need/beg for help and advise

 

This is definitely a thread that's been needed. I agree, knowledge is power.
One recurring electrical problem on our trucks is grounds. You can never have too many.
When I'm using the factory ground I make sure the terminal is clean and where it attaches I use a dremmel tool to make sure the area is clean to shinny metal. Then I use some dielectric grease to help seal the area against moisture.
It doesn't hurt to add grounds either. I added one from the frame to the starter and another from the radiator support to the frame. After I mount the body and bed I'll add more.

 

You bring up a good point. A lot of electrical problems occur from bad ground connections. I also clean all my contacts and put dielectric grease on everything.
For example, I used a wire wheel on my dremel to clean the fuse holder clips in the fuse panel, then wiped a little grease on there. I also squirt a little grease on each of the connections in a connector. Helps them slide on and off a little better.

 

I like that little soldering jig .
On the crimped connectors, I'll agree to a point. Aftermarket crimp connectors are junk. They'll "work" but that's about it, not a very good connection. The factory connectors are also crimped BUT it is a very tight connection. These are called open barrel connectors and take a special pair of crimping pliers, regular crimpers won't work.

 

If ya need waterproof or easy to separate connectors, then opt for a Weatherpack connector kit (Delcity PN 75045). There's my $20 SportComp tach ready to go.

Get yours at Del City - Wiring Products and Professional Electrical Supplies

 

instead of using a dremel, try using this Bonding Brush 5/32" Used that is for a 10-32 screw, screw and nut then another nut to hold grd leads, aviation has a lot of tools and processes that can solve automotive problems

 

Bonding Brush 5/32" Used
Hmmmm, I like that tool.

 

+1 on having the right crimper, I have a few myself:



That is a small collection of mine. I have large tool box for only electrical tools. I agree, ditch the splices, and solder wires together.

 

As a former avionics tech, I concur. Here's a good source for hardware, consumables, materials, etc. : Aircraft Spruce

 

HEY SPARKY, I'm an A&P myself

 

I'm familiar with aircraft hardware, I used to get Aircraft Spruce's catalogs.
I joke that it's been so long since I flew a plane, the last plane I flew was a Ford Tri-motor which is actually true but it was back in the late 80's not 30's .

 

I've got a new harness from bronco graveyard it's a centech I should have it in a few days I'll let you know how it looks.

 

Sparky? Ha! That's what we called the electricians.

Avionics techs (AT) are known as "Tweets". Here's what I looked like when Zeros (Officers) broke my planes... especially when they spilled coke or coffee in the keyboards....

 

Thanks! That little tool has really saved my butt. It sure is handy.

Sorry I didn't make myself clear. I meant the covered butt connectors. I hate those things Much rather solder. For terminals, what you have shown is really the good stuff

It's funny, there's a lot of prior airplane experience here I was a crew chief for a while and also taught aircraft wire repair for the Air Force.

Anyway, here's a few more tricks I didn't post earlier. When you want to remove just about any connector on these trucks, here's a poor man's trick I use. I have a snap-on scribe to release the lock. You can also buy a Ford-specific tool. You just push it in and then pull the connector out from the back



I also use liquid electrical tape in limited applications.

It is good for minor insulation touch ups, and when I have a loose wire I don't want to cut off (for future use) I dip the end to prevent any arcing/shorting/corrosion.