'02 alternator???

[Meierznutz]

My rig is charging at just about 12v Run it for a while (5 min) and the volt gauge takes a dump and falls to 8v Click the key off and on quick and its back to almost 12v
Is there a way to test the Alt in the truck? I know these are externally regulated and the reg is part of the PCM ($550 from dealer and $85 to code with vin and miles) I found a rebuilt on line for $350 but want to make sure that its the PCM.
Also I hear a clicking from behind the drivers dash once in a while but that sounds like a relay kicking out due to low volts, is there a ground hidden somewhere I should be cleaning?
Thanks in advance... Chris

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'02 2500 QC SB 6 Sp, Con-OFE, Banks Brake and Monster Exhaust, JL Stealth Sub, AM Lunar gauges, Air Dog Raptor, Home built Hybrid 35/40 pushing 33psi!
Is there a Mega Cab in my future??? P.S. This truck for sale.

[clc]

I am sure there is a way to test the alternator on the truck. I have never had to do it and I don't have the schematic so I can't write up a procedure. I don't always trust the onboard gauges but I imagine you have other reasons to suspect the charging system. Do a search on "external regulator". I have seen (but not read) posts on that subject. Perhaps they will give you some insight. Good luck. Let us know what you find.

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96 3500 4WD, 47RE, gauges; 97 3500 4WD 47RE, gauges; 97 3500 2WD 5-spd; all club cab. 98.5 2500 2WD SB, 5-spd, gauges, quad cab

[Rollin Coal]

chris, if you need a hand i'm about 15 minutes from oakville

let me know 203-441-2053

Ryan

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Thanks to Diesel Auto Power ...... '01 - 2500 53 Block ...... 600+ HP Build Up Thread

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[AllanP]

Go up to Autozone or another parts store. Most of them can test your alternator in the truck. I just had it done a few months ago.

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'99 3500 QC SLT Laramie, Leather. 4x4 auto trans, Suncoast VB, TSC 89% TC, Firestorm2 inj, Edge w/Attitude, Raptor lp, Glacier F/W Separator Combo, 4" Str8t Exhaust, High Flow Intake, Ats Exh manifold, Super B turbo. Amsoil dual filters. Non 53. Original owner.

[Meierznutz]

Thanks all. I pulled the alt and had it tested but the kid didn't have the pigtail to hook up, just the ground and 12v pos from the charge stud. It was making about 10.3 v. With the alt unregulated I expected more and was not happy. I went home and was looking in the back of the unit when I saw 4 very corroded wires from the field windings. One was rotted through and looked more like a coper spark plug gap (green and about as wide as a good gap) so I ordered a new alt. $185 and she's putting out 13.63 at idle and nearly 14 with the A/C, lights, and radio on at 1700 rpm.
To think I almost listened to the guy with the 200amp alts for sale " They never go bad. It's the PCM" (yeah right, $550 and another 85 to program, then I need the alt too...thanks)
Chris

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'02 2500 QC SB 6 Sp, Con-OFE, Banks Brake and Monster Exhaust, JL Stealth Sub, AM Lunar gauges, Air Dog Raptor, Home built Hybrid 35/40 pushing 33psi!
Is there a Mega Cab in my future??? P.S. This truck for sale.