Having trouble finding the resistor wire or ballast resistor on my 65 F100 Custom Cab. Any clue as to where either one would be located? How big is the ballast? if it was covered by black tape could I tell that it was thicker or would it be the same thickness as the wire? Also, I don't see a Pink resistor wire going to the ignition switch but there is an old, thick cloth wire that is connected and runs somewhere behind the dash that gets warm to the touch when the ignition is on, could this be it the resistor wire? Guessing this is the culprit to my starting nightmares because I am running a new coil that has the built in resistance and think that now maybe my resistance is too low to produce a stong enough spark? Started first try yesterday, turned off, tried a second and a third and a fourth and a fifth, etc...has brand new motor in it with no miles, new accel points eliminator with new coil and was running and starting fine until two days ago when i was loading on the trailer. Now it just turns over and doesn't start (except the mysterical first try yesterday after installing the original solenoid relay back in the truck cause the new one the previous day went haywire and was turning over after the key was turned off, put into gear and the "I" and "S" wires were pulled off of the relay, I had to physically disconnect the batt cables. I am lost and confused, need help before I sell the truck. I hooked up a volt meter to my ignition wire and "s" wire going to the coil and I only have 3.8-4v. when I checked it was bouncing from 4 to 8 to 6 to 10 to 7 to 5 etc... going to try a new coil today and go from there, start replacing stuff I have already replaced I guess.

 

Yes the cloth covered wire is in fact the pink one. It plugs in to the run side of the switch and is integral to the firewall plug.

You possibly burned out the ignition by only feeding it 9 volts while running.

You need to check the plug where the wires enter the firewall as they like to corrode and break apart causing voltage flutter.

Garbz

 

ok so if I am running a new accell points eliminator kit and a new coil that reduces the voltage also that would explain why I only have 4v coming out cause it is getting reduced twice, once with the resistor wire and once again with the coil thus not producing a spark hot enough to start, I am going to do two things when i get home, I am first going to connect the old original stock coil that doesn't have the resistor built in and see if it starts, or I can run a bypass wire from the ignition to the coil to give it the full 12v the new coil wants

 

does that resistor wire go to or do anything else on the vehicle other than the coil, that would prohibit me from replacing with a new wire to the new coil?

 

You can bypass the resistor wire and run 12v to your new coil. The resistor wire is only used for the coil.

 

Ok, I think I will bypass to see if it fixes first before I remove it totally, thanks for the info

 

went home connected the batt cables after being off all nite, started right up, let it run for a few moments, then shut off and tried to restart, nothing. bypassed transistor wire, installed old coil, nothing, installed new suggested coil 8104 for accel points eleiminator, checked voltage at the coil and was better around 9.58, tried to start, still noting, though maybe flooding after first start so pulled plug, plug good, checked spark, spark good, threw tools in the box and went in the house, not good, puzzled and pissed at the same time, this isn't rocket science but it sure feels like it is

 

COLF-12250-A .. Resistor Wire-Ignition Coil (Motorcraft DY-37).

61.49" long / Color coded PINK / 1.30-1.40 ohms resistance / #20 gauge wire.

 

going to try replacing the switch now, maybe something is getting hot or shorting out, it looks like the factory one so it is 45+yrs old

 

Ok, I going to add my two cents to this. The resistor wire doesn't having anything to do with starting. You should have 12v to the coil while the switch is in the start position. This is through the start relay,via the s and I terminals. When you release the switch, power then runs through the resistor wire and into the coil. I don't know if this helps but at least you know how it supposed to work. As far as the starter still cranking after you pulled the relay wires sometimes the relay contacts arc and stick. When you disconnected the battery leads the relay cools down and they can work normal again. Many times you can give the relay a rap and it will stop cranking when stuck. Hope this helps, Rob