internal voltage reg

[71GMC72]

I have been looking at old posts about converting ext voltage reg to internal and from what I understand I am supposed to connect the brown and blue wire together and connect the white and red wires together all at the ext voltage reg plug in. Now I am wanting to clean up all my wires can I just connect directly the brown wire coming out of wire harness bulkhead to blue wire at the alt and just connect the white wire at alt to the main red hot wire on the back of the alt, is this the same results or am I missing something? Thank you.

[DPowers]

http://67-72chevytrucks.com/vboard/s...d.php?t=119379

[71GMC72]

Yes that is the exact post I was refering to but what I am wanting to find out if I can eliminate ext voltage reg and plug by just splicing the brown wire directly from the firewall wire harness bulkhead to the blue wire in alternator and just splicing the white wire in alt directly to the red hot wire. From what I can see it should come to same results without all the wires on wheel well.

[VetteVet]

You can but you have it backwards, the brown wire goes to the white wire and the blue wire goes to the red wire.

This is the best way to do it.



The SI alternator is the internally regulated alternator with terminals 1 and 2 instead of the factory R and F terminals. The brown wire from the firewall ends up on 1 and the red wire ends up on 2. Toddtheodd just loops the no.2 red wire over to the large post on the back of the alternator in the link above. It works but it works better if the no. 2 wire is connected to a junction with the battery and alternator away from the alternator. This is called Remote voltage sensing.

If you intend to go with a newer CS style alternator, then you need to insert an 85 ohm 5 watt resistor in line with the brown wire and the alternator pins will be the L terminal and the S terminal .

[oldschool18]

Do whatever vettevet says...............I followed the same diagram he posted above and did exactly what he said and it worked perfect. Vette I know I told you before and I'll tell you again, Thank you for the help

[VetteVet]

You're very welcome. VV

[71GMC72]

Yes that is what I was trying to do, remove external regulator and excess wires and rewire directly , thank you VettVet.

[VetteVet]

Y/W
Don't forget to post back when you're done, with the results.

[michael bustamante]

Elominate the white wire. Eliminate the blue wire and connect the brown wire only. You can even cap off the red at the. Ext regulator plug and and hook the other wire on the alternator to the red lead on the harness to the alt

[71GMC72]

so do I cut the brown wire before or after the diode thats spliced in a foot from the old ext volt reg I am trying to get rid of ? Seems like that should be part of old system and not the new one right ?

[VetteVet]

Originally Posted by 71GMC72

so do I cut the brown wire before or after the diode thats spliced in a foot from the old ext volt reg I am trying to get rid of ? Seems like that should be part of old system and not the new one right ?

The factory did not have a diode or a resistor in the brown wire or in the wires to the alternator. This was a Band-Aid fix for engine run-0n after the key was turned off. It prevents current from the alternator from back-feeding to the ignition switch. If it is a diode and not a resistor it would have to be installed with the arrow pointing towards the regulator. Otherwise the alternator would not charge.

If it were me I would cut the brown wire at the firewall and put in a new wire straight to the alternator.

If you were installing a newer CS style alternator then you would have to install a resistor in the brown wire to protect the alternator diodes.

Here's a diagram for that.



The horn relay is in the pre 67 trucks in the charging circuit in this diagram. In the later trucks they bypass the relay.

[michael bustamante]

Hmm mine did not have a diode.but do not have a 6 guage dash either. I connected to the brown wire directly from the plug to the external regualtor.

[71GMC72]

Well I hooked it all up direct as vettevet diagram . I did cut the brown wire with the diode included when I connected it. I tossed out the external reg and cut the blue and wires a foot from the firewall bulkhead and taped up. End result is charging at 15 volts and I can disconnect the negative battery cable and it keeps running which it didn't before which was why I started this conversion to start with. All in all a success , thank you everybody that advised.

[slikside]

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[BLT gmc]

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