+12v with key on

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Baker7888

G-Body Guru
Dec 3, 2021
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Not sure what I said was vague... you want to use a random 12v wire without knowing what else it may go to.
All i know is it’s hot with key-on per my
test light. It went to the now deleted two prong oil pressure switch. My thought was since the switch has been deleted, the wire would stay hot-key-on all the time.
 

ELCAM

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Jun 19, 2021
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The brown power wire at the oil pressure switch goes to fuse number 2 top row on the right. Goes through a 20 amp fuse to the 12GA orange wire on the ignition switch, this circuit also powers fuse 4 and 6.

Pull the fuse and see if the wire goes dead, then you know what circuit you are using.

1978-1981 Pontiac LeMans Fuse Box Diagram.jpg
 
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Baker7888

G-Body Guru
Dec 3, 2021
665
115
43
Maine
The brown power wire at the oil pressure switch goes to fuse number 2 top row on the right. Goes through a 20 amp fuse to the 12GA orange wire on the ignition switch, this circuit also powers fuse 4 and 6.

Pull the fuse and see if the wire goes dead, then you know what circuit you are using.

View attachment 207350
Awesome, thank you. I will confirm tonight when I get home.

Will this circuit be suitable for my needs or should I change it?
 

ELCAM

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Jun 19, 2021
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If I understand correctly this is being used for the control side of the relays. Bosch relays draw about 150mA to energize the coil. Running 4 relays will not draw a full amp of current. The circuit will have lots of excess capacity.

If all you run off this circuit is the 4 relays I would change the fuse to a 5 amp or smaller.
 
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Baker7888

G-Body Guru
Dec 3, 2021
665
115
43
Maine
If I understand correctly this is being used for the control side of the relays. Bosch relays draw about 150mA to energize the coil. Running 4 relays will not draw a full amp of current. The circuit will have lots of excess capacity.

If all you run off this circuit is the 4 relays I would change the fuse to a 5 amp or smaller.
Yes you understand correctly. Thanks for the great information. So did fuse #2 only protect the oil pressure switch wire or are there others as well?
 

ELCAM

Royal Smart Person
Jun 19, 2021
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On the diagram I have the #2 fuse only powers the electric choke there is nothing else on the circuit.
 
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Baker7888

G-Body Guru
Dec 3, 2021
665
115
43
Maine
On the diagram I have the #2 fuse only powers the electric choke there is nothing else on the circuit.
Ok awesome. I will verify tonight. I looked for this a while back in my haynes but they did not have it.
 
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