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Help to Identify Power Wire

To make a long story short, dropped and re-installed by engine/tranny last year. Hooked battery back up and promptly melted my engine wiring harness. Had to get one made ($$$) as I could no longer find one to buy.

New harness installed, ready to try again. Put multimeter between battery + and frame and found continuity (bad!). Unhooked main power cable at starter to isolate the new harness- still a short. Unhooked the mess of red wires bolted to the + side of the battery and found one that goes to ground. The wire as a brown plug that has a Red and small black going in and the red out to the + post. Also has this funny black terminal-like box.

Before I go much further in tearing the car apart to see where this wire goes, does anyone have any ideas.

Its a 1988 911 turbo (930). The only aftermarket part I see is a stereo, and its not the power for that.


Old 10-27-2014, 07:40 AM
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The brown "plug" appears to be a splice connector which allows power to be fed to the black box. Now, from your picture, it looks like a black wire leaves the black box (to the left, behind the thick, black covered wire), is zip-tied to a red wire, and is connected with a non-factory connector to a red wire. Is this correct? If so, then it appears to be a non-factory addition and you need to find where that red wire terminates or, cut the connection to the red wire and see if that solves the short to ground. You can always re-connect the wire with another non-factory connector. It may also be possible to open the brown plug and disconnect the black wire from the power cable and see if that solves the short.
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Last edited by ossiblue; 10-27-2014 at 07:57 AM..
Old 10-27-2014, 07:55 AM
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your second paragraph is a bit confusing, and perhaps better pics.

use a test light. connect it between either the positve cable and battery of the neg cable and battery. the light is now the load.
if the light comes on, then you have a short to ground.

i would start with the batt cable off the starter, the 14 pin connector removed from the relay panel, the 14 pin connector removed from behind the engine. if the light comes on, start removing fuses one at a time.
make sure doors are closed and no other interior/trunk/glove box lights are on.

you cant do this by measuring voltage. you have to either use a test light or you have to measure current. even the smallest amount of current draw will measure 12v.
if you go from the batter + to chasis, that is the same as going from + to - on the batt.
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Old 10-27-2014, 08:06 AM
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You might have bad relay .Did you replace relays after the short .
Old 10-27-2014, 12:37 PM
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Did not replace relays. Just left off the red wire with the black wire. Tried to start car. Starter engaged but would not disengage even after I turned key off. Clearly I have damaged something else when the main harness shorted.
Old 10-27-2014, 01:27 PM
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It is important to proceed with caution to make sure there is not a dead short, but you have to also realize that reading continuity from the red to ground does not necessarily mean a short. There are certain devices that receive power when the car is shut off. Things like the clock, radio, alarms, etc. will give a reading on a continuity meter.
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Old 10-27-2014, 01:57 PM
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either the solenoid is sticking onthe starter, the starter is sticking to the flywheel or you have a bad ignition switch.
not sure if you could wire the starter wrong so that it does that.
did you do anything to the starter?

use a test light. it acts as a load so it limits the current flow so wires dont melt. isolate the back of the car like i said and make sure the rest of the wiring is ok first.

you need to make sure what ever you wired up wrong that started all this is fixed.
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Old 10-28-2014, 04:05 AM
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Thanks Ed. Never thought of power to devices when the ignition is off. Just really nervous after melting the engine harness last time.

Bought a test light yesterday to help with the test process.

Was also thinking the solenoid might have taken a hit given that it starts and doesn't stop. Probably easier to test than the ignition switch so I'll start there.

thx for all the advice folks. Will update when I find the gremlin

P.S. I always thought my human patients were hard to diagnose! Automotive wiring is a mind bender!
Old 10-28-2014, 05:27 AM
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the solenoid is just coil. its pretty tough. it would not get damaged from what you did. if the solenoid goes bad, as far as the coil, it will not cause the starter to keep running. what can happen is the solenoid gets stuck, but that is a mechanical issue, not electrical.

what did you connect wrong?

thats a strange looking ground wire in the pic.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[__] RUNNING:[] NOT RUNNING:__2000 MER E320 WAGON [] WRECKED:[]RUNNING:
Old 10-28-2014, 06:57 AM
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Sent you a PM to offer over the phone troubleshooting for the electrical.

Old 10-28-2014, 01:21 PM
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