|Topic Review (Newest First)|
|08-12-2019 10:26 AM|
We have this issue on our fleet trucks there is a break in the purple wire on alternator take and run a jumper to battery box on pass side, this will prevent you from replacing whole harness. Typical symptoms are overcharging which makes bcm shut down to protect itself and just a nagging battery light even though its charging when you check batteries
Also take a set of jumper cables and go from battery to battery if this removes the light the wiring harness between batteries has loosened at a splice
|07-14-2019 10:21 AM|
|[email protected]||Definitely sounds like a broken wire or two in that wire loom. Passenger side, bottom front of the engine, there is a tray that has the wires that go between the batteries and the alternator. Its in there and you cant miss it once you take a closer look with a flashlight and mirror. I had the exact same problem, replaced the alternator AND both batteries and the charge light kept coming on. Charge would fluctuate between 11 and just over 14 which is what it should be. I finally found the wire, insulation cracked and innards corroded right through. I soldered in a replacement section and problem solved, but not before too much money needlessly spent. Charging now starts at low to mid 12VDC at idle, then climbs nicely to 14.2 VDC.|
|04-03-2019 06:26 PM|
could just overlay a wire.
That harness is a bit of a pain to deal with
|04-03-2019 04:35 PM|
|powerstrokeshellback||Check your grounds too|
|04-03-2019 04:07 PM|
|2014six.7||There’s a video some where on you tube that shows a chaffing point for a wire bundle under the passengers side front of the truck. The problem comes from the wires being zipped tied too tight from the factory. You mentioned you cut the zip ties on the harness and gained continuity. Go back and inspect the wires for chaffed areas.|
|01-25-2019 11:18 AM|
Update. I pulled the generator out, had it rebuilt, the truck was fine for 2-3 days, now the battery light randomly comes on and off while driving. Not really sure what to make of this anymore.
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|01-20-2019 01:38 AM|
|zerim5000||I've always just pulled the cables off the batteries once running to test the alternator. Turn every single electrical thing you can on and pop the cables if it has issues then the alternator is likely bad. I'd say belt but nah the new belts on these are double sided and very grippy though if the belt is on wrong maybe. You should be getting close to 14v though when running so less than 13v is bad.|
|01-19-2019 08:35 AM|
|01-19-2019 08:34 AM|
|Larry1013||That is a code P0620 I think.|
|01-19-2019 08:05 AM|
Update: I checked continuity from PCM to generator harness, didn't get anything. Then I went under the truck and cut the zip ties that hold the wires into the loom that run under the crank pulley. Checked again, now I have continuity. Plugged everything back in, started the truck, now I have P0620 - Generator Control Circuit code. The truck still isn't charging.
Might just have to take it in to the dealer and hope for the best. It's cold as hell out here.
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