The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Electrical

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 04-14-2019, 12:35 AM   #1
andrewpclayton
Registered User
 
andrewpclayton's Avatar
 
Join Date: Aug 2017
Location: Eugene Oregon
Posts: 108
12Si Alternator Install Diode with Battery Gauge

Working on a 69 GMC 1500 and I have been following VetteVet's posts as best I can, but this is absolutely not my strongest area. Hopefully he can chime in

I am swapping in a 350 engine from a 77 4wd (I think) that has the alternator on the passenger side. As of now the engine is out, and nothing is plugged in but I want to have everything ready to plug and go. Will be installing an alternator from a 85ish C10.


I have taken the wiring tape apart and removed the plug for the external harness, so its set for the brown wire to go from firewall to #1 on the alternator

I have a battery gauge, I assume this means there isnt also a light, thus I need the diode?

If that is the case, I cannot figure out what a diode even looks like, nor which to get.


Can one of you, any of you, all of you tell me

A) am I on the right track in terms of from the harness, the brown wire going to #1, the red going to #2 and the junction box, and power from battery via starter

and
B) if the diode is necessary, can someone link me to the correct unit to buy?

thanks!
__________________
1969 SWB (conversion) GMC C1500 SBC350
2019 Harley Street Bob Stage II

Instagram: @nevernotchevy
#eugenec10s #northwestc10s
andrewpclayton is offline   Reply With Quote
Old 04-14-2019, 12:37 AM   #2
andrewpclayton
Registered User
 
andrewpclayton's Avatar
 
Join Date: Aug 2017
Location: Eugene Oregon
Posts: 108
Re: 12Si Alternator Install Diode with Battery Gauge

Also my apologies, I know there are many similar posts, I just cant find confirmation re the diode
__________________
1969 SWB (conversion) GMC C1500 SBC350
2019 Harley Street Bob Stage II

Instagram: @nevernotchevy
#eugenec10s #northwestc10s
andrewpclayton is offline   Reply With Quote
Old 04-15-2019, 03:57 PM   #3
VetteVet
Msgt USAF Ret
 
VetteVet's Avatar
 
Join Date: Jan 2005
Location: Kalamazoo, Michigan
Posts: 8,274
Re: 12Si Alternator Install Diode with Battery Gauge

If you have the battery gauge you also have a resistance wire on the key switch at the auxillary terminal along with a large brown wire (12 gauge). This resistance wire is there to give the alternator the resistance it needs in case the light fails or if you don't have the light, in your case.
Just go ahead and connect the brown wire to no;.1 and it should work fine.

Be sure you run the red output wire to the same junction as it was and not directly to the battery or the starter post or the battery gauge will not work.

A diode is a small device in a wiring circuit that will only allow current to travel in one direction (like a check valve) It is different than a resistor which will allow current to travel in either direction but applies a resistance to the current to lower the voltage to a load which requires a lower voltage.

The diode will have an arrow showing the direction of flow of the current and a resistor will have a series of bands on the body that are color coded to show its resistance value. Some have the value (ohms) labeled on the body.

https://www.youtube.com/watch?v=I24e7gF6k5o
__________________
VetteVet

metallic green 67 stepside
74 corvette convertible
1965 Harley sportster
1995 Harley wide glide

Growing old is hell, but it beats the alternative.
VetteVet is offline   Reply With Quote
Reply

Bookmarks

Tags
alternator, alternator conversion, electrical

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 12:23 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Copyright 1997-2013 67-72chevytrucks.com