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LeesTruk · 08-28-2020, 11:53 AM

Didn't want to hijack TBrown's posting on alternator issues, so I'll start my own, and I don't mean to drag up a continuing alternator problem...

Anyways, My truck is a '80 C10, w/5.3l from a '05 Tahoe, using the DR44g alt. The truck has been running now for about 4 yrs. with no electric concern, other than the 13+ volt output. After reading Tbrown's question about resistors on the exciter wire (brown wire), I was curious. With key on, exciter voltage is 10vdc, battery voltage is 12.7vdc. So. I checked my wiring, brown wire to C2 pin 15 (gen. control), grey wire to C2 pin 75 (duty cycle signal). Both check good continuity. From searching here, a past posting from DAYj1 on this subject shows a mod that can be made to the DR44g, but also, a schematic for the gen III LS in trucks. The schematic shows that a third wire, C1 pin58 (serial data to the IPC) is used in the charging system. Is this needed for the PCM to allow proper charging? If not, would a resistor added to the brown wire allow my alt. to charge properly? If it's as simple as adding a resistor, then I'll do that .

08-28-2020, 11:53 AM	#1
LeesTruk Registered User Join Date: Mar 2015 Location: Manchester, CT Posts: 429	Alternator dilema Didn't want to hijack TBrown's posting on alternator issues, so I'll start my own, and I don't mean to drag up a continuing alternator problem... Anyways, My truck is a '80 C10, w/5.3l from a '05 Tahoe, using the DR44g alt. The truck has been running now for about 4 yrs. with no electric concern, other than the 13+ volt output. After reading Tbrown's question about resistors on the exciter wire (brown wire), I was curious. With key on, exciter voltage is 10vdc, battery voltage is 12.7vdc. So. I checked my wiring, brown wire to C2 pin 15 (gen. control), grey wire to C2 pin 75 (duty cycle signal). Both check good continuity. From searching here, a past posting from DAYj1 on this subject shows a mod that can be made to the DR44g, but also, a schematic for the gen III LS in trucks. The schematic shows that a third wire, C1 pin58 (serial data to the IPC) is used in the charging system. Is this needed for the PCM to allow proper charging? If not, would a resistor added to the brown wire allow my alt. to charge properly? If it's as simple as adding a resistor, then I'll do that .