5.3 wiring question

[cash]

Where is the alternator plug? all I have is the hot wire connection, I pulled the harness out of 2005 silverado, cant find the plug

[vandejr]

do u mean where on the harness or on the ecu?
http://www.lt1swap.com/2004vortec_pcm.htm
it shows the gray wire on port 75 of the ecu on the green bundle and most alternators are one wire arent they?

[cash]

On the harness

[Jones'n]

Should be right next to the connector for injector 1 and the wiring for the IAC and TPS (with a cable TB)

[the_merv]

It has a Red Wire, 4-pin Connector.

[cash]

Thanx

[busta9876]

here's the run down.

LS1's used a single RED wire in a 4 position plug as pictured a few posts above.

Vortec 4.8/5.3/6.0 series used sometimes a single brown wire in the same location as the red above, and sometimes 2 wires, brown and gray. - 4 position plug.

Around 2005 or 2006 on the Vortec trucks, the PCM no longer connects to the alternator on some vehicles, and now there is a generator-battery control module, or GBCM for short. This monitors current draw on the negative battery cable, and controls the alternator its self. These alternators had a narrow 2 pin plug with two wires, gray and brown.

I have seen in some late model harnesses a 3rd blue wire, unknown what it is for, as it does NOT go to the PCM.

[fast400]

There are still two pins in the pcm that can be used in the 2006 pcm instead of using the battery control module. If you want to use the module instead, I have a new one you could have for $20.

[68Problemchild]

So if you are putting a 4 prong plug above into a two wire, would the grey and brown both tie to the one alternator wire in slot B on the 4 prong?

[jsafe]

http://67-72chevytrucks.com/vboard/s...d.php?t=433009

nice thread here too