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Re: [GMCnet] Alternator Warning Light [message #88986] Thu, 17 June 2010 11:45 Go to next message
KB is currently offline  KB   United States
Messages: 1262
Registered: September 2009
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Senior Member
Ok, here's a weird newbie question: our alternator light only comes on when the key is in the "accessory"
position, instead of in the "on" position as it should. Clearly a wiring problem somewhere. Anybody have
a suggestion on where physically to look for the problem?? On the steering column, or ??

thanks,
Karen
1973 23' Patience Tester
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Karen 1975 26' San Jose, CA
Re: [GMCnet] Alternator Warning Light [message #89011 is a reply to message #88986] Thu, 17 June 2010 14:40 Go to previous messageGo to next message
Oldngray is currently offline  Oldngray   United States
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Registered: August 2009
Location: Punta Gorda Florida
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Karen, I do not have a clue why, thankfully, mine works the way it should.
I just removed my fuse and reinserted it and now I don't get a "glow", maybe the fuse had poor or no contact after all these years.


Richard MacDonald Punta Gorda, Florida Sold our TZE April 2015
Re: [GMCnet] Alternator Warning Light [message #89030 is a reply to message #88986] Thu, 17 June 2010 15:59 Go to previous message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
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Senior Member
Karen,

That IS weird. The power to which that bulb compares the alternator output
should come only from the Inst/Tran fuse, which is supplied from the IGN
buss -- it should NOT receive power when in the ACC position. Do the other
instruments also become active in the ACC position?

I'd start troubleshooting by removing the Inst/Tran fuse and checking for
voltage on the should-be-cold side in different switch positions -- you'll
likely find that contact hot with ACC selected. Comparing your wiring with
the wiring diagram should eventually reveal the problem. It's probably
something changed by a PO. The steering column and its assorted wiring is
NOT likely to be involved.

Just a reminder to everyone: My son Alan at mgcads.com offers wiring
diagrams in LARGE sizes that can be read by old eyes. The 175% size is
probably the best compromise for legibility and manageability.

Ken H.
Americus, GA
'76 X-Birchaven
www.gmcwipersetc.com


On Thu, Jun 17, 2010 at 12:45 PM, KB <kab7@sonic.net> wrote:

> Ok, here's a weird newbie question: our alternator light only comes on when
> the key is in the "accessory"
> position, instead of in the "on" position as it should. Clearly a wiring
> problem somewhere. Anybody have
> a suggestion on where physically to look for the problem?? On the steering
> column, or ??
>
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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