is one of these the coil wire?

[redstone65]

1970 F-100 Ranger. 360 with a/c. Project page.



It's a bundle of 4 wires coming through the firewall here:



Two of them read 12v while the key is in the "on" position and zero when in the "off" position. The other two read zero all the time. I'm guessing one of those 12v must be the coil wire. But, I thought the coil wire would be a "resistor wire" (pink). At least that's how it was on my '65. I can trace them out with the continuity. tester, but figured I'd ask first to save some time since digging up behind the dash is a pain.

[390FE1972]

According to the 1970 master wiring diagram: http://www.fordification.com/tech/wirin ... master.jpg , and the color wiring chart: http://www.fordification.com/board/Ford ... -chart.gif , the 16 wire is red with green strip and goes to the ignition coil, the 31 wire is white with a red strip and goes to the oil pressure sending unit, and the 39 wire that is red with a white strip goes to the temp sending unit. Hope this helps!

[390FE1972]

I see that the diagrams did not show up on my last post. On the Fordification website where it says Site Features there is a section called diagrams and schmatics, click on that, go to section H; wiring diagrams, then go to the 1970 wiring diagrams and you will see the 1970 F100, F250 wiring diagram, click on it. To find the Ford truck wire color and gauge chart, it is under the Misc. Wiring Schematics.

FYI

[sargentrs]

Yes, the red w/green stripe. I believe it has the smaller right angle boot. Here's the pages 390FE was trying to post. http://www.fordification.com/tech/wirin ... master.jpg and http://www.fordification.com/tech/wirin ... -chart.gif The one with the big, straight boot is most likely for the carb throttle solenoid if you have one, they were optional with A/C equipped trucks. If you don't have one, its a good source for a switched hot accessory add on like a relay.

[Ranchero50]

Ditto, oil pressure, water temp are the red and white ones / white and red ones (forget which is which)

ignition is red and green.

[redstone65]

Thanks guys!

and the color wiring chart

I had the schematic already, but not the color-code chart. I didn't know that existed. Nice!

and you will see the 1970 F100, F250 wiring diagram

I read in a different thread that for F-100's with guages instead of idiot lights you need to use the F-350 schematic. Is that right?

ignition is red and green.

Do you know if that's a resistor wire, or just a normal wire? I'm hoping it's normal because the resistor wire is a pain. Leave the switch in "on" too long and it tends to melt.

The one with the big, straight boot is most likely for the carb throttle solenoid

I don't see a choke lever on the dash. I'm guessing it's electric choke?

[sargentrs]

The ignition wire is a normal wire from the 3 prong connector to the coil, however, it's a resistance wire from the connector back to the ignition switch. It's not the wire that usually burns up, it's your points. That's why you should never leave your key on in the run position without the engine running. Always use the accessory position on the key if the engine is off.

Can't tell about your choke without seeing your carb. The carb solenoid was designed to increase the throttle when the A/C compressor kicks on at low rpm's. If you don't have A/C you probably don't have the solenoid. It would be mounted on your carburetor with a plunger engaging your throttle linkage. Not to be confused with an anti-stall dashpot which is just a spring loaded diaphragm that keeps your throttle vanes from slamming shut when you let off the gas pedal quickly.

[Ranchero50]

Ditto, without the resister wire (@ 7' long pink guy behind the dash) the points would burn up. Instead that wire reduces the voltage.

[redstone65]

Ah, I think I understand now. When my '65 burned up the pink wire it was definitely pitted points at that time so that makes sense. I switched to electronic distributor after that so the pink wire is gone now. I guess I'll do the same thing on this one after we get it running. One less thing to troubleshoot.

[sargentrs]

[timachone]

You can also leave the resistor wire as is and wire your electronic dizzy to a switched 12 volt source like a relay if it would matter not to cut the original harness. That's like I did with my Mach 1 and what I will do to the F 250 - both with a Pertronix I, Flamethrower coil and the relay kit. Works like a charm without any troubles...


Tim

[lloyd70cs]

not to thread jack this but the wire from distributor to coil, is that to negative or positive. in my vast foresight I wrote "top" of coil, then threw out the old one and bought new one.

[sargentrs]

Distributor to coil negative (-). Ignition wire from switch to coil positive (+).

[lloyd70cs]

thanks sargentrs!! You keep finding me!

[sargentrs]