Fuel Pump Relay Wires

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Sep 26, 2009 | 07:36 PM

megtom2

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Racer

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From: Cordova TN

Fuel Pump Relay Wires

I am an idiot. While wiring the pigtail to the pump relay on our 86 I didn't notice there were two red wires until after I had cut them and now it is impossible to see which red is A and which one is D. If I hook the battery up will one show 12v with the key turned to on or will one show 12v with the key turned all the way to crank the car? Thanks

Sep 26, 2009 | 07:48 PM

megtom2

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Racer

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From: Cordova TN

Looking at the schematic D goes to the aldl and A comes from the ECM. Shouldn't one and only one of the wires give 12V with the key in the on or crank postition?

Sep 26, 2009 | 08:18 PM

MK 82

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From: Palm Beach

Take your multimeter and set it to read resistance. Put one probe on G on the ALDL. Take the other probe and check continuity with each red wire. The one that shows continuity is D.

Sep 26, 2009 | 08:24 PM

rodj

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From: Australia

Quote:

Originally Posted by megtom2

Looking at the schematic D goes to the aldl and A comes from the ECM. Shouldn't one and only one of the wires give 12V with the key in the on or crank postition?

Should be no power on D ;It is only a means of sending 12v to the pump for check purposes.

Last edited by rodj; Sep 26, 2009 at 08:27 PM.

Sep 26, 2009 | 10:01 PM

megtom2

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Racer

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From: Cordova TN

I figured it out by connecting B,C and E then taping off one red and having my wife turn the key while I checked voltage on the other red. Came up to 12v or close so I then knew that one was A.
Thanks guys

Sep 26, 2009 | 11:48 PM

MK 82

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From: Palm Beach

You taped B and C and E together? I hope you didn't do it for long because B is an always hot Battery feed and E is ground. Can you say short circuit?

Sep 27, 2009 | 12:01 AM

megtom2

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Racer

Joined: Aug 2009

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From: Cordova TN

Quote:

Originally Posted by MK 82

You taped B and C and E together? I hope you didn't do it for long because B is an always hot Battery feed and E is ground. Can you say short circuit?

No, I connected those three to where they were obviously supposed to go. The only question were the two reds.