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I've got problem, starter ignition wiring?

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Old Mar 16, 2010 | 07:17 PM
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I've got problem, starter ignition wiring?

Heres the story, It's a 1975 f250 4wd Highboy, 360 motor, 4 spd trans. Anyways to get to my problem. I have the two wires that were not hooked up at the solenoid. I put a test light on them trying to figure out which one was the starter side and the ignition side. Well with the test light, turn key on, both wires are hot. and they stay hot until I turn key to off position. The wiring doesn't look bad, it's not butchered. Far as I can tell everything is where it needs to be. I traded for this truck awhile back, just now getting around to trying to get it working properly so I can use it this week. I'm hoping the lights and stuff are in working order.
Another question is what is the need for the ignition wire going to the Ignition side of the solenoid?
 
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Old Mar 16, 2010 | 07:25 PM
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From: horton, ks
red/blue wire goes the S terminal on the solenoid.

brown wire goes to the I terminal, that is if its a dual post solenoid

if a single post solenoid, just hook up the red/blue wire
 

Last edited by 82ford302; Mar 16, 2010 at 07:33 PM. Reason: couldnt read a terminal lol
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Old Mar 16, 2010 | 07:28 PM
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The "I" or brown wire sends full voltage to coil during cranking.

Josh
 
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Old Mar 16, 2010 | 07:37 PM
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Yes it is a two wire solenoid. Once the truck starts what powers the coil? I still trying to figure it all out so I have a better understanding of how it all works. Thanks for the info so far.
 
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Old Mar 16, 2010 | 08:10 PM
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Once the key is in RUN, power goes thru the switch, thru a resistor wire (pink) to the coil.

The voltage is FULL power during cranking to help get the engine started, once it is running power is resisted down to around 7 volts.

Josh
 
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Old Mar 16, 2010 | 09:44 PM
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Alright understand that, I still haven't figured out why the starter wire red/blue stays hot, even when the key is back in the run position. If I'm thinking correctly it should only have power on it, while the key is turned to start position? What I did to temp. fix it is left the red blue wire off, and jumpered in a starter button. I would like to figure this problem out so I can use the key and only the key.
 
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Old Mar 17, 2010 | 09:09 PM
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Is there any kind of relay's in between the ignition, and the solenoid??
 
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Old Mar 17, 2010 | 09:50 PM
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Nope. These trucks are old school.

The red/blue comes from the ignition switch thru the neutral safety to the solenoid. The only way that wire would continuously get power is if the ignition switch went bad or a PO hacked the wiring and crossed that wire.

Josh
 
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Old Mar 18, 2010 | 09:05 PM
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I was thinking it might be a bad switch. The wiring fortunetly isn't hacked. So I might try another switch to see if that solves the problem. I've got it rigged with a starter button know. Force of old habit is turning the key all the way over and obviously nothing happens. DUH! push the button, Dummy!!!
 
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