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Need 12V source active with key in Run and Start

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Old 07-21-2014, 11:00 PM
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Need 12V source active with key in Run and Start

I'm converting from a carb setup to a FAST EFI setup on my 84 Camaro. I need to hook up my fuel pump (the relay), distributor, and a wire from the ECU to 12V sources that are active with the key in both the run and start positions.

Any ideas on some good wires/places to tap into for this? I would prefer one near the fuse block if possible.

Thanks!
Old 07-21-2014, 11:18 PM
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Car: 89' IROC-Z
Engine: LO3
Transmission: 700R4
Axle/Gears: 10-Bolt/2.73
Re: Need 12V source active with key in Run and Start

The radio? Both Hot and Acc circuits are on the radio harness.
Old 07-22-2014, 01:36 AM
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Car: 1989 Iroc-Z Camaro
Engine: TBI,5.0
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Axle/Gears: Eaton Posi,3.42,LPW Ultimate Cover
Re: Need 12V source active with key in Run and Start

Probe a few of the empty slots in the back of your fuse box one at a time with a multi meter. Pos. lead on the meter touching the slot and the other lead to ground with the key in the "ON" position. Voltage should only be there in that position and start.

I use a spade connecter and insert into the slot I want to use to control the "low" amp wire on a fan relay, etc.

These slots are not to be used with high amp applications and need a relay if that's what your trying to do.

I use a small inline fuse on that wire just before the connection to the slot.

This way your not tapping into existing wires that are already being used.

Last edited by Ron U.S.M.C.; 07-22-2014 at 01:44 AM.
Old 07-22-2014, 01:50 AM
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Re: Need 12V source active with key in Run and Start

^ What he said. Ron would you post your relay circuit diagram in here?
Old 07-22-2014, 03:27 AM
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Re: Need 12V source active with key in Run and Start

This is a completely independent circuit including from the stock wiring and is as simple as they come.
It is a adjustable temperature controlled switch that is installed on the relays low amperage ignition controlled ground wire .That way even though the switch is rated at 30amps it does not use it. Much safer for the fan switch this way.

This circuit is wired with heavy gage where it needs it to handle a large high amp fan but can be used with any.(smaller fan can use a 30amp relay if you want.)

Here's the $17.00 adjustable temp. controlled fan switch.( you do not use the diagram that comes with it ).
It is universal and you might need to enter the part # to see it. =Part # 733653
http://www.autozone.com/autozone/par...67187_69565_0_

I have two of these circuits controlling two different fans. One set at 190* and a second as back up set at 200*. With a 180* thermostat. It keeps the car within that range even in traffic.( I painted mine black ).

Side note = If you decide to build one I can tell you a very simple way to set the controller to the temp. you want.



Last edited by Ron U.S.M.C.; 07-22-2014 at 03:50 AM.
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