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Discussion Starter #1
I need help finding the ignition resistor wire in the wiring loom behind the dash. If anyone has done this on 78 bronco I could use your help. I need to do this to install a ready to run distributor to by-pass the ignition box, I am so tired of my truck not starting.
I thank you in advance for your help
Outlawbob
 

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Post what you find. I have an 80 and I need to bypass the resistor when I move to the EEC-IV setup.

I can describe what my EVTM shows but not sure how applicable it’ll be to your ‘78.
 

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1978 351m c6
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I need help finding the ignition resistor wire in the wiring loom behind the dash. If anyone has done this on 78 bronco I could use your help. I need to do this to install a ready to run distributor to by-pass the ignition box, I am so tired of my truck not starting.
I thank you in advance for your help
Outlawbob

You talking about the resistor wire for the coil that brings it down to 6v or 9v or so when driving?

Bud
 

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I removed and replaced mine. from memory for what it is worth it starts just after the ignition switch. if you open up the main wire loom behind the instrument cluster you can see it there and follow it. If I remember correctly it is a different looking rubbery feeling wire not vinyl like the rest of em, it may have a extra sleeve on it also.
If you don't want to remove it, you could bypass it using the " the other wire" at the starter solenoid, That wire gives the coil full 12v at cranking via the solenoid and bypasses the resistor wire the feeds from the ignition switch.
 

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If you open it up you will find where the resistor wire ends (heading towards coil end, not ign switch) you will find where its spliced with an additional wire, that additional wire heads direct to the starter solenoid.
 

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Discussion Starter #6
Thanks, but with a 43 year old wiring harnbess I'm going to replace the whole thing so i don't have any other issues.
 

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1978 351m c6
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You don't really need to dig out your ignition wire. Just need to find a 12v keyed hot wire under the hood and plug it straight in to it. Just make sure it is large enough gauge to supply power to the coil. That's what I did to my jeep when I dropped an hei distributor in it. Good luck

Bud
 

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My father was trying to talk me into that with my bronco but I don't mind the spark control module. That and I already purchased the ignition control module when I figured out that my distributor was needing a rebuild. Also the hei distributor is bigger and hits things. I thought about it though.

Bud
 

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it is the wire with the rubber like insulator

it’s not that easy to just replace. It is part of the plug on the Ignition at key on dash
It is a solid wire and not stranded if I remember right
I chose to be rid of that wire entirely
I used a relay under the hood to put power directly from the battery to ensure 12 volts

energize the relay coil with key in run position
Problem. When turn key to start engine it kills power to all accessories (heater fan ,radio etc)
So I couldn’t find a wire that would hot the coil when cranking engine (Key turned to start )
Solution. I put in a push button to crank engine
 

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it is the wire with the rubber like insulator

it’s not that easy to just replace. It is part of the plug on the Ignition at key on dash
It is a solid wire and not stranded if I remember right
I chose to be rid of that wire entirely
I used a relay under the hood to put power directly from the battery to ensure 12 volts

energize the relay coil with key in run position
Problem. When turn key to start engine it kills power to all accessories (heater fan ,radio etc)
So I couldn’t find a wire that would hot the coil when cranking engine (Key turned to start )
Solution. I put in a push button to crank engine
 

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Its also worth mentioning that the I terminal also gets 12v while cranking and most vehicles don't use that terminal. Or at least the ones I have owned and worked on.

Bud
 
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