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charging system idiot light ? [message #254460] Sat, 05 July 2014 18:04 Go to next message
bpimm is currently offline  bpimm   United States
Messages: 211
Registered: June 2013
Location: Washougal Washington
Karma: 2
Senior Member
My alternator light doesn't come on when the key is turned on but does come on when the engine starts.
Voltages at the alternator are
Batt 15.2V
Field 15.4V
Sense 14.11V

So it's charging but the light is on.
I don't have an APC yet.
It just started doing this part way through our maiden voyage with the coach a couple weeks ago and I want to get it sorted before we take it out again.

any ideas what could be doing this?

Thanks

EDIT: I just ran to radio shack for a diode and installed the diode in lew of the APC, quicker this way. no change.

Brian & RaeDean 1973 26' #383 Washougal WA

[Updated on: Sat, 05 July 2014 19:40]

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Re: charging system idiot light ? [message #254472 is a reply to message #254460] Sat, 05 July 2014 20:05 Go to previous messageGo to next message
Craig Lechowicz is currently offline  Craig Lechowicz   United States
Messages: 541
Registered: October 2006
Location: Waterford, MI
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Going by somewhat feeble memory, but I kind of remember that a bad positive diode in the diode block inside the alternator can cause this.

Craig Lechowicz
'77 Kingsley, Waterford, MI

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Re: charging system idiot light ? [message #254473 is a reply to message #254460] Sat, 05 July 2014 20:07 Go to previous messageGo to next message
bpimm is currently offline  bpimm   United States
Messages: 211
Registered: June 2013
Location: Washougal Washington
Karma: 2
Senior Member
Was a bad connection on the gauge cluster so the light wasn't getting it's power and was grounding the hot side of the bulb through the whatever else it feeds in the cluster.

Brian & RaeDean 1973 26' #383 Washougal WA

[Updated on: Sat, 05 July 2014 20:07]

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Re: [GMCnet] charging system idiot light ? [message #254485 is a reply to message #254473] Sat, 05 July 2014 23:09 Go to previous messageGo to next message
Mr ERFisher is currently offline  Mr ERFisher   United States
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Registered: August 2005
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Read here
http://www.gmcmotorhome.info/engine.html#alternator

Erf

Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and -------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

> On Jul 5, 2014, at 6:07 PM, Brian Pimm wrote:
>
> Was a bad connection on the gauge cluster so the light wasn't getting it's power and was grounding the hot side through the whatever else it feeds in
> the cluster.
> --
> Brian & RaeDean
>
> 1973 26' #383
>
> Washougal WA
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Re: [GMCnet] charging system idiot light ? [message #254502 is a reply to message #254485] Sun, 06 July 2014 08:59 Go to previous message
bpimm is currently offline  bpimm   United States
Messages: 211
Registered: June 2013
Location: Washougal Washington
Karma: 2
Senior Member
It turned out to be a combination of 2 things, the pins on the circuit board were all loose so I soldered them to the board, and then there was a broken run on the board as well in the 12V supply from the pin. I cleaned the run and bridged it with one of the cut off leads and solder. (lead was from the diode I had just installed). The pin connections are loose on the speedo board as well so I will solder them as well before I put it back together.

Gene, the symptoms matched the blown instrument panel fuse.

Thanks

Brian & RaeDean 1973 26' #383 Washougal WA

[Updated on: Sun, 06 July 2014 09:01]

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