Looking for 12v source while cranking
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TECH Veteran
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Joined: Mar 2009
Posts: 4,444
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From: Pompano Beach FL
Looking for 12v source while cranking Tried this in the pcm forum and didnt get much of anything. Anyway I need a 12v source that will give me power when in cranking and running but off when the key is off. It just needs to trigger a relay I thought about using a fuel injector/coil wire as the tirgger but I really dont want to place a draw on that circuit.... Any suggestions? If people have used that circuit as a trigger let me know
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Joined: Oct 2002
Posts: 603
Likes: 1
From: Decatur, IN
12v source You want to make sure you have a 12v source that is labeled for START as well as RUN (Start is what used to be called Crank in some wiring diagrams).
I wouldn't recommend the coil/injector circuit because if you shut the engine off at just the right time you will have the coil energy back feeding on that circuit (since it can't fire the coil).
The AC clutch circuit is also not a good choice because it is tied to the AC relay and the AC clutch and the AC clutch is a fairly noisy device.
The best source for a 12v switched source on a 2002 F-body is going to probably be:
PCM IGN fuse, 15A.
Circuit # 439.
Wire should be pink and blank.
The fuse panel for that is labeled underhood, bottom.
I wouldn't recommend the coil/injector circuit because if you shut the engine off at just the right time you will have the coil energy back feeding on that circuit (since it can't fire the coil).
The AC clutch circuit is also not a good choice because it is tied to the AC relay and the AC clutch and the AC clutch is a fairly noisy device.
The best source for a 12v switched source on a 2002 F-body is going to probably be:
PCM IGN fuse, 15A.
Circuit # 439.
Wire should be pink and blank.
The fuse panel for that is labeled underhood, bottom.
Tried this in the pcm forum and didnt get much of anything. Anyway I need a 12v source that will give me power when in cranking and running but off when the key is off. It just needs to trigger a relay I thought about using a fuel injector/coil wire as the tirgger but I really dont want to place a draw on that circuit.... Any suggestions? If people have used that circuit as a trigger let me know
