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AC Delco Alternator

Post by FAB » Sat Jul 20, 2013 3:52 pm
Hi

I have a 45amp AC Delco fitted to the camper, the other day the charge light started to flash on and off even on revs, then the light would stay off as normal for a time, I have put a meter across the battery and am only getting 12.42v even on revs, new battery fitted and it is nearly flat now.

I have taken the alternator off the vehicle, I wish to check the wiring supplying the alternator to make sure everything is ok before I go spending money on a new alternator, I have one main lead and one small lead in a connector that plugs into the alternator(this connector and the wires going into it does not look too clever), to check continuity of each of these wires where do they go? (i.e where is the other end of these wires)

Also is there any other checks I can make on the actual alternator to test it, I do not have an amp gauge just a multi meter?

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Re: AC Delco Alternator

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Post by Phil Bradshaw » Club admin » Sat Jul 20, 2013 4:48 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 4681
Main brown wire goes to the starter solenoid.
Thin brown+yellow wire goes to alternator warning lamp via bulkhead multi-pin connector between bonnet hinge & wing on left side when viewed from the front.
Can check warning lamp circuit by grounding brown+yellow wire with ignition switched on: lamp should stay on bright.

Symptoms sound like be brushes worn down past limit & now one of them is held just off the slip ring by its braid wire.
Not too hard to fix & brushes are cheap. As it happens I'm working on the Howto for Delco alternator overhaul at present but it's nowhere near ready yet.
Meanwhile I've toggled the relevant section of the GM manual for you to see full resolution: check your email. :)

Re: AC Delco Alternator

Post by FAB » Sun Jul 21, 2013 5:35 am
Thanks Phil I will check the continuity of the main wire to the starter solenoid, the small wire should be OK as the light does come on and off so power must be going through it. :o

I can not open the link to the GM Manual on google docs, it says it is unavailable to virginmedia customers after I try to log in. :cry:

Jim

Re: AC Delco Alternator

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Post by Phil Bradshaw » Club admin » Sun Jul 21, 2013 7:39 am
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 4681
It can be worth checking the brown+yellow wire because the warning lamp circuit influences the voltage regulator output to the rotor winding and thus alternator output. That said, if the lamp doesn't light with the alternator plug disconnected then short circuit between alternator and lamp can be ruled out.

Google drive issue is my fault. :oops:
Email on its way.

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