The power (12 volts +)to the coil goes to a splice no matter what position the ignition switch is in (start or run) In start, the power goes thru splice to coil to negative ground to complete the circuit.

In run, power goes thru ballast resistor to same splice to coil to ground.

Draw a line on a piece of paper that is 6 inches long. Label the left end of the line S(start). On the right end of the line draw a box and label it COIL. Put a dot at about the 3 inch point. The dot will represent the splice.
Draw a 2 inch vertical line starting at the dot in the down direction. Draw a line to the left parallel to the start line starting at the bottom end of the vertical line. Draw a box in the bottom line and label it RESISTOR. Continue the line til you get to a point below the left end of the first drawn line and label that end S(start).

An electrical circuit will work only as long as there is a complete path for current to flow. If you draw the diagram you will see how the coil is powered in start and in run. Any break in the bottom line (RUN), Bad switch, wiring or a bad ballast resistor, to the splice in the start line will cause your problem.

I have worked in the Electronics and Electrical field since around 1963. I was an Electronic Tech on B-52s and KC 135 tankers. Most of my remaining career was as an Industrial Electrician. I am not the sharpest knife in the drawer by any means. A lot of times I have to try to gnaw my way thru problems.

Good luck.

 

Thanks again PayDay. As soon as I can locate the circut w/the resistor wire I will simply run another line w/a known good quality resistor wire, then disconnect the original. In my experience that is the best way to fix bundled wires (simply run new.) I perused the Haynes manual w/o success. Couldn't find the starter switch in the diagrams as it read just like the Chilton diagrams I have"...to ign switch." Like I said, it has stalled and I have brought it back to life by placing the ign switch in "Start" so it must be there...Right?! Intermittent electrical problems are the best BTW: Switch was replaced last year, and coil some years ago. Sounds logical so far. I am an ex-auto mechanic and body repair tech, paratrooper, teacher, and present day contractor...and I can make round squares (no lie.) Also not the sharpest blade in the drawer, sounds like we both can cut though. Ciao! Bob-O

 

http://www.lloydsautolit.com/search.cgi?year=1984&make=Fordtruck&category=Wirin g+Diagrams

 

I simply detest electrical problems that are intermittent. I have repaired many problems when I couldn't say how I fixed them. All I could hope for was they wouldn't happen again. I have never been able to fix a problem if it is working fine when I am trying to repair it.

When you are using the start position on the ignition switch, you are actually bypassing the resistor and supplying a full 12 volts to the coil. Your coil isn't designed to run like that. It could overheat and burn up if it is used like that a long time.

If you really want to Southern engineer the truck, you could run a wire from a fuse thru a toggle switch mounted underneath the dash, thru a known good resistor to the battery terminal on the coil. I don't know what size the fuse should be. The Haynes manual doesn't list a fuse. It indicates a fusible link is used. I would try one around 5 amps. The new circuit would work just as good. It would probably be a good anti-theft device also. ;0)

You could still use the ignition switch to start the truck.

Good luck buddy.

 

Hey CTUBUTIS, Thanks! It sounds like a good tool to have in your back pocket and the book is on order PAYDAY, you'll never guess what I found trying to find the blk/grn wire to the fusable link under the dash...A 30 amp fuse at the top of the fuse block that had really bad contact thru its legs to its wires and was arcing and overheating (dunno why it didn't blow) it had melted the surrounding plastic fuseblock and was intermittently contacting/opening...C'est la vie, eh? Ahh, when you seek Grasshopper! I've cleaned the spade terminals on the fuse and the related female connectors, but was getting dark by the time I found it and haven't replaced anything else. When I get the time I'll remove the wires and place a separate 30A inline fuse on that circut. The fuse block appears to have solid metal contacts that feed many fuse circuts, so I'll have to be attentive to simply removing the feed. You all have been a great help and I appreciate it!! Merci beacoup

 

If you dont mind asking, why do you have a button starter for this?

I have a Mercedes-Benz that came to me with a button starter under the dash. Why? Because the P.O. wouldn't replace a $40 ignition/steering lock assembly... used price. I replaced the assembly in about an hour, and have not regretted it at all.

 

Keep on trucking. ;0)

 

Et tu Payday! Homesuser01 Ign key-starter switch went defunct and at that time I had plenty of copper wire and a momentary contact switch on hand. Works just like the '55 Pontiac we had when I was a kid Have since replaced the entire switch unit, but never hooked up the starter relay wire to the switch again. Everthing works on my unit too (AC, cruise, dual tanks...) Removed the rad fan some years ago & replaced w/elect unit from scrap yard. Works good and may even be improvement. Truck is wonderful and doesn't let me down (just needs some tweakin' every now and then...) I have the same problem w/gas stations tho about 10-12mpg. Ciao, Bob

 

Yeah. We had a 1940-something Ford truck when I was a kid that had the push-button starter, too.

I thought about that truck while starting up my Mercedes everytime I drove it.

 

It was due to the ability of the starter switch to go into the start position that gave me the opportunity to discover that the circut worked only in that position. Was useful when in traffic and it stalled, that I could just place it in Start position and keep it running. After 24 years it has some minor glitches? Better than some of the horror stories I've heard of new and nearly new ones.