Ignition voltage dropping resistor location

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Apr 10, 2007 | 11:33 AM

metalZ

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Ignition voltage dropping resistor location

I was wondering where the voltage dropping resistor for the ignition is located in a 1981 F-250 would be located and what color wire it is in. I am not sure what I am looking for. Any help would be appreciated.

Thanks
MetalZ

Apr 10, 2007 | 12:09 PM

Franklin2

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From: Virginia

Ford did not actually use a resistor. They used special resistance wire of a certain length. So the length of wire from the coil + to the keyswitch is the resistor.

Apr 10, 2007 | 03:22 PM

Mil1ion

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The resister wire comes out of the igntion switch shown here.

Your coil should show 6-8 volts while engine running.

12volts with key in start position.

Last edited by Mil1ion; Apr 10, 2007 at 03:24 PM.

Apr 10, 2007 | 04:16 PM

subford

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From: Easton,Ks

Quote:

Originally Posted by Franklin2

So the length of wire from the coil + to the keyswitch is the resistor.

I know we have always said this and I may be wrong but what I have seen is that this all takes place within 6 inches of the Ignition Switch with two splices.
The Photo is of an 89 E150 but this part of the wiring seems close to the earlier Fords. It is raining right now or I would go look close at my 83 F150.

The Photo:

Apr 10, 2007 | 04:31 PM

Franklin2

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From: Virginia

I didn't think 89 had a resistor but that sure does look like the picture above in Dennis' post. That makes sense too with the bypass wire were it is when they started incorporating that into the ignition switch.

I bet all the harnesses with the ignition switch bypass look like that, and the earlier ones with the starter solenoid bypass are the ones that may look different.

Apr 10, 2007 | 05:19 PM

subford

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From: Easton,Ks

Also I know in the 89 E150 there is a fuse link after the splice with the Start bypass and before it gets to the Ignition system on the red wire with a green stripe. I do not know if trucks have this fuse link or not but this fuse link is only shown on the big foldout diagram and not on the E&VTS Manual or any other diagrams I have seen. However the Resistance wire is shown in the all the diagrams for the 88 & 89 E-series but not in the F-series.
I have never seen this fuse link brought up in any of the posts.
Here is a photo.