Need to identify ignition wire under hood (1 Viewer)

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How do identify an ignition wire under hood? I have a 1972 FJ40 with a sbc 350.

I am trying to install electric fan;


Specifically, a pink wire named "Ignition hot".

2. Install thermostat into a water jacket in the head or intake manifold (Done). Unroll the PINK wire from the parts kit. Strip ¼” of insulation from the copper on one end. Crimp one of the female spade connectors onto this
wire. Push the spade connector onto one of the male spades on the thermostat. Route the PINK wire from the thermostat to a 12 Volt ignition hot source. Cut it to length and use the blue Posi-tap to make the connection.

Thanks in advance, ,
Jim
 

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If you are running an HEI distributor the ING wire would be going to the terminal tagged BATT on the cap. Because you are running an SBC your stk wiring colors may have been altered from stk colors.
 
If you are running an HEI distributor the ING wire would be going to the terminal tagged BATT on the cap. Because you are running an SBC your stk wiring colors may have been altered from stk colors.
Thank you for the quick response. I will take a look at my distributor.

This user group is awesome.
 
Connect your pink wire to the + terminal on your coil.
I've got some wires coming from under this tab on top of my distributor.

Screenshot_20230921-101511_Gallery.jpg


20230921_101144.jpg
 
Since you have an SBC I assume you have an internally regulated chevy alternator.
There may also be a 12V switched wire where the stock toyota external voltage regulator that used to be on the drivers side firewall.

This wire may be gone depending how hacked up the stock wiring harness is.
If you are looking under the hood towards the drivers seat, the voltage regulator was to the right of the steering column where it goes through the firewall.

Just another possible option for you. Good luck.
 
The wire going to the BAT terminal would be hot when the key is on the on position. You could tap off of that wire. If you have a test light you may be able to find other wires that are hot under the hood when the key is on too, as @WildernessRimFab metioned.
 
How have you cooled your SBC B4 installing this electric fan?
 
Since you have an SBC I assume you have an internally regulated chevy alternator.
There may also be a 12V switched wire where the stock toyota external voltage regulator that used to be on the drivers side firewall.

This wire may be gone depending how hacked up the stock wiring harness is.
If you are looking under the hood towards the drivers seat, the voltage regulator was to the right of the steering column where it goes through the firewall.

Just another possible option for you. Good luck.
Great reply. I'll look there too.
 
The wire going to the BAT terminal would be hot when the key is on the on position. You could tap off of that wire. If you have a test light you may be able to find other wires that are hot under the hood when the key is on too, as @WildernessRimFab metioned.
I do have a test light. Don't know why I've not used it. Thanks for the quick response.
 

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