Hey All,

1970 F-100, 390, 3sp O/D, 2wd

Recently I've been going through a tune-up on the truck and getting familiar with it. Reading about the ignition system etc, and realized that I don't think I have a Ballast resistor wire on the coil There is some jenky wiring that was performed by the PO and may have taken it out not knowing because I can't find it. Where should this pink wire with bullet connectors be located on the truck? Is it under the dash or visible in the engine compartment? Because if I don't have one, I want to put one on there. Thanks

Dan

 

If you've got an electronic ignition and a 12v coil then you don't want the resistance wire in place... so before you replace it be sure a more modern ignition hasn't been retrofitted.

 

The factory resistance wire is in the main harness behind the instrument cluster. It is pinkish and is usually doubled back upon itself. It is not inside of any electrical tape.

 

I have the original points ignition. I looked under the dash and didn't see anything but I will look again then. Is it solid pink, or pink and some other color? Thanks

 

It's solid pink. Mine has faded out to a pale pink that almost looks light brownish.

 

Ok cool. Shouldn't I be able to check voltage at the coil with it running and tell if it is there or not? Thanks

 

Yes can do test with key on engine off (KOEO). You should get either close to battery voltage, or about 1/2 if resistor wire is intact.
Another test would be to remove the 'I' terminal wire from starter solenoid. If it still starts the resistor wire has been bypassed.

 

The faded pink resistor wire should have a female bullet type looking wire end connector on the +side of the coil. May look brown or it's all greases black looking until you unwrap the oem tape on it.

The coil +wire may show 9-12 volts not running 6-9 volts running:

The pink wire it located on the ign.switch plug, is where it starts out working it way to the coil.

Orich

 

Ok, thanks I will go check that. I checked the coil itself a minute ago and it shows 1.6 ohms between the pos and neg but between pos and the center is only 8.26 K-ohms and what I found said that it should be between 9 and 13 K-ohms. So, it is a bit below the low side. I would like to replace the coil soon and also put Motorcraft points and condensor in it but wanted to hash all this out first in case there is an issue.

Dan

Dan

 

So, I have 6 volts at the coil with KOEO. Assuming resistor wire is in place. Thanks

 

Points........B8Q12171A (DP12) Available from Ford.
Condenser..C9AZ12300A (DC13A) Available from Ford.
Coil............B6A12029B . Discontinued. Let me know if you want me to run this number on my locators.

 

C0LF-12250-A .. Resistor Wire-Ignition Coil (Motorcraft DY-37) / Obsolete - Available NOS & from auto parts stores.

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

ALL 1960/70 FoMoCo vehicles.

 

Hey, thanks much for the part numbers Jeff and Bill. That is great. I found that Summit sells the points and condenser, so do you think those are what I'm looking for? And do you think I would gain anything in quality by buying a NOS set off say Ebay or something? Just curious. One last thing, Do you think that an AC Delco coil will be my best bet on quality? I know how critical these components are. Thanks again

Dan

 

BTW thanks for the offer to run the coil Jeff. That would be great if you get a chance. Probably the ol mustard top

Dan

 

Stay with the Ford/Motorcraft condenser FOR SURE. So many of the others are overseas JUNK. There have been hundreds of problems with bad/faulty condensers on this site alone!