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alternator gurus needed, 4 gauge rewire gone bad?

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1Gina2G

10+ Year Contributor
810
2
May 6, 2011
Beaufort, South_Carolina
okay everyone to start off here are threads I've already posted, directly related-

http://www.dsmtuners.com/forums/new...r-melted-wire-underdfusebox-wire-diagram.html

http://www.dsmtuners.com/forums/newbie-forum/470711-way-remove-wires-alternator-plug.html


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this is from link 1, shows how I currently have the alternator rewired, which I'd like to think I have it hooked up correctly since I hooked up the new wires as I took the old wires out but didnt take note or ever got any additional pictures.

Anyways, I rewired with 4 gauge as shown and the alternator which was just replaced by re manufactured oem and a new battery, and charged the battery just fine with no electrical problems.

after a long drive one day i smelt a burning wire under the fusebox so I shut everything off and disconnected the battery and left to cool. later found out that the new 4 gauge wire coming from the alternator was melted at the very last 3 inches or so but very badly. no other wires were on it so it was the only thing damaged, was sure it was a bad connection so I replaced the wire with a whole new run but this time I soldered the ends of the wire at the krimps and now with everything back in place & plugged in the alternator does not produce above 12.5v while on.

the fuseable link for the alternator is new. theres also continuity through the entire 4 gauge run, from battery end to fuselink side1 to fuseside1-fuseside2-to alternator. testing in ohms with the battery totally disconnected of course..

thing is nothing's happend to my alternator/generator relay located by the factory boost control solenoid -- but after research still havent found a way to test its function with the mulitmeter or other.

http://www.dsmtuners.com/forums/art...55-alternator-issues-brake-battery-light.html

the battery and brake lights are actually on and stay on with the keys in. I understand the lights are a redflag to the alternator after reading this link but
the alternator is still brand new and was just aproaching 500 miles of use, but i've discovered i may need to replace the pigtail from the harness that plugs into the alternator, even though I can read 12v through the plug and by grounding elsewhere.


would either problem with the relay or the harness plug cause the brake & battery lights to show? chances of new alternator already fried?


heres a post from a thread trying to find out info about the alternator harness plug-
http://www.dsmtuners.com/forums/maintenance-repairs/372254-alternator-plug-testing-question.html

Measure the voltage on the G terminal. If near zero, you either have that wire grounded or the ECU is grounding it. When that terminal is grounded (by the ECU normally) the stock 2g alt is designed to output 12.5v max. This is used during heavy acceleration to keep the alt from loading down the engine so more power is available to the drivetrain.

2g alt and battery test on the car: http://www.dsmtuners.com/forums/new...reeway-electrical-problems.html#post151165661

Another source (besides a weak battery) of a perfectly good alt not charging on a 2g is a burned out dash charge light AND the generator relay (which is not really a relay) not functioning - one of the 2 must work for alt to work. The generator relay seems to get easily physically destroyed for some reason on 2g's (and missing on some 99's). It's next to the turbo wastegate solenoid.


apparently my ecu is grounding the green wire in the harness plug as it reads 5 volts but unsure. How does one go about having the ecu unground the wire? i've already had the ecu reset by having the battery disconnected..
 
Last edited:
well I was hoping someone would've chimed in with something, but as an update -

-I made sure all bolted on connections from the new 4 gauge wire are nice and tight,
- rescraped the side that the original wire melted on to show shiny copper on th e fusebox.
-took a second look underneath the fusebox to make sure again that no wires came loose or were damaged in anyway.
-ohmed out all fuses with a good multimeter
-replaced alternator / generator relay MD113566 and did not get 14v, so i cut the plug off with some length of wire on it and attached the relay with female krimps and rechecked, still just 12.5 at the most with the battery/brake lights on/off

so I'm really thinking its the harness connector that plugs into the alternator, i found a generic one that says for mitsubishi alt. 4 pins but i'll update if it fits.
 
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