Electrical questions
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Electrical questions
On a 75 F100 where would be the best place to pull key on engine off power from. I am adding several little items to the truck and need to know where to power the relays from without killing the battery.
Lead Driver
Joined: Jul 2017
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From: San Jose, CA
Do you want power in both the ON and ACC key positions?
Do you know if you need any of them to be on both in ON and START at the same time? Using the ACC position of the ignition switch "usually" results in having no power on the circuit when in the START position.
I'll leave the details of where stuff is to those more familiar with the differences of '77 trucks to the '79's (which is what I have) but there are some basic wires you can use.
I usually don't like triggering stuff off of the Green w/red wire at the voltage regulator, but since it's just a relay or three, that should not disrupt the function of the regulator. This circuit is hot only in RUN and START, but not in ACC.
For an ACC and RUN circuit, you could literally run a wire from the back of the ignition switch to your relay bank/fuse panel as your power circuit.
I'm trying to think of another, more handy one, but that might take awhile. Need lunch first!
If you're planning to mount the relay/fuse panel over on the driver's side, is there a wire there for the dual-battery option? If you don't have the option, there is likely a wire still over there that would have been used to trigger the isolator relay that Ford used for their setup. I believe it should be a Black w/green trace wire?
Take a peek over in the driver's corner to see if that wire is just hanging out there somewhere.
Hope that helps a little. Hopefully someone will have more '77 under-hood experience to guide you.
Where is your hoped-for mounting position for the new stuff?
Paul
Do you know if you need any of them to be on both in ON and START at the same time? Using the ACC position of the ignition switch "usually" results in having no power on the circuit when in the START position.
I'll leave the details of where stuff is to those more familiar with the differences of '77 trucks to the '79's (which is what I have) but there are some basic wires you can use.
I usually don't like triggering stuff off of the Green w/red wire at the voltage regulator, but since it's just a relay or three, that should not disrupt the function of the regulator. This circuit is hot only in RUN and START, but not in ACC.
For an ACC and RUN circuit, you could literally run a wire from the back of the ignition switch to your relay bank/fuse panel as your power circuit.
I'm trying to think of another, more handy one, but that might take awhile. Need lunch first!
If you're planning to mount the relay/fuse panel over on the driver's side, is there a wire there for the dual-battery option? If you don't have the option, there is likely a wire still over there that would have been used to trigger the isolator relay that Ford used for their setup. I believe it should be a Black w/green trace wire?
Take a peek over in the driver's corner to see if that wire is just hanging out there somewhere.
Hope that helps a little. Hopefully someone will have more '77 under-hood experience to guide you.
Where is your hoped-for mounting position for the new stuff?
Paul
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Joined: Jul 2005
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Wire it to an Accessory circuit. On my '77, when the key is in the Accessory position, everything in the cab receives power - except the ignition. The On/Run position powers the ignition and all accessories.
Unless you only want the new stuff on when the ignition is on... If that's the case, wire it to the ignition.
Unless you only want the new stuff on when the ignition is on... If that's the case, wire it to the ignition.
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