Redroad, You're The Man!!! Thanks so much for your detailed explanation and diagrams. I'll test the plug and switch when I get home tonight.

I want to open up the harness to see where the brown wire from the starter solenoid splices into the pink wire and see where the brown wire goes from there. Also want to find the other end of the pink wire splice and find the parallel wire and do some testing.

 

I had a little time tonight to do some continuity and voltage testing on the old and new switches and here's what I found....

Both the old and new switch had continuity at all terminals (with the switch on) except the P1 and P2 terminals. However, the P1 terminal is the brake switch and the P2 terminal has no wire going to it. So this test sounds normal and both switches tested good.

I also did a voltage test on the wires in the plug on the back of the ignition switch with the key on. I tested all the terminals, but I focused mostly on the two terminals that had the parallel wires coming out of the switch; ST terminal (Red w/blue, Red w/white) and I2 terminal (Red w/white, Orange w/green)....

Excluding P1 & P2 terminals, all of the terminals had 12v to it with the key on except the ST terminal. The ST terminal had 9.83 volts when cranking the motor. The cranking voltage seems a little low, but it's enough to power up the coil and start the engine.

The red wire in the ignition module plug still didn't have any voltage and this really has me confused as to why.

The color of the wires in the two plugs going into the ignition module are: 4 wire plug = green, black, orange & purple. 2 wire plug = red & white

I haven't had a chance to open up the harness all the way to the pink wire splice on both ends, but plan to do that in the coming week or so.

Upon further inspection, I was wrong about the coil wire going into the distributor plug & then to the coil I was going off of bad memory when I stated that. Actually, the green wire goes into a rectangle shaped plug that goes through the firewall on the driver's side. I assume this wire splices into the pink wire. The plug has one green/red coil wire going into the plug and 2 red wires coming out of the plug and going through the firewall.

Any thoughts???

 

It is going to be easier if you take some pictures so we cab be sure we're talking about the same thing .. When describing a wires color list the base color then the color of the stripe ..

Watching Gold cup soccer tonight

 

You're absolutely right about naming the main color first and the striped color second. I've got so many irons in the fire right now and my brain is fried and I simply got the color sequence backwards and didn't catch it. My apologies. For the most part I have been naming the main color first follow by the striped color.

I think I need to finish opening up the wiring harness to the pink wire splices and do some continuity and voltage testing. That's the plan anyway, unless someone has any ideas...

I'll try to take some pictures, but my camera sucks so not sure if I will be successful. At the very least, I'll refer to the ignition plug diagram to describe the wiring instead of the ignition switch and maybe that will help clarify this mess

I won't get a chance to work on this again until next week. We're moving this Saturday, but as soon as we get moved, I'll get back to it.

Enjoy the soccer game. Thanks for all your help. I really appreciate it...

 

Good luck with move .. and we will pick it up when you have time again

 

Redroad--I have a question for you....Are you positive the red wire at the duraspark plug coming through the firewall is supposed to have 12v??? Let me explain why I ask you this question...

I have two 1979 Broncos that are 20 miles away at my mom's house and I was out there today working on one of them (had to install a new fuel pump). After I got done and got the Bronco fired up and running, I decided to test the voltage at this plug since it's the exact same setup as my 78 F150 that I'm having problems with. So I tested the red wire in the plug with the key on and there's absolutely NO voltage at this wire. However, there is 12v at the white wire. This confuses me since the diagram seems to be backwards from what's actually happening. I get the exact same results on my Bronco that I do my truck. The white wire in the diagram goes to the "Start" position on the ignition switch, which I would assume wouldn't get any voltage until it is being started. However, that's not the case. It's getting 12v with just the key on....Weird!!!!

So can I just run my ballast resistor off this white wire instead of the red wire at this plug? I'm assuming I can, but I thought I'd verify this with you guys. Hopefully my only problem might be the resistor wire. But in the mean time I want to bypass the resistor wire and see if I can get it started.....

Thanks for the advice...

 

You can use any 12v source that produces 12v in the "on" position in conjunction with the provided ballast resistor to get the result your looking for ..

 

Well after a weekend spent moving, I do have an update on the truck's electrical problem. Last Friday night; the night I brought the uhaul home to start loading it, I took 20 minutes and gave it one last shot to get the truck running. I hooked up a wire to the white wire in the factory ignition module plug (plug with the red & white wire) and connected it to a ballast resistor & from there I ran another wire from the other end of the ballast resistor to the MSD 6A box. Then I clipped the factory resistor wire. When I turned the switch on, my tach responded and the light on the 6A box lit up, which gave me a ton of hope. Then I cranked the motor and it fired up!!!!!!!!! I have never been so relieved and happy is such a long time. Talk about coming through in the 11th hour...

So now I will be reinstalling the throttle body for the EFI (I put the carb back on to rule out the EFI as the problem) and replacing the resistor wire once I get one ordered. I've driven the truck the last two days finishing up our move and so far no problems.

This has been a very frustrating and stressful month since my truck went down, but I would like to thank all of you for your input, advice and help. Without your help, I might not have figured this out. So thank you very much everyone! You guys rock!!!! I hope I can return the favor to someone.....

 

Great I'm glad you got it A broke truck at zero hour on moving day is bad news ..