| Alternator lamp not working [message #270449] |
Mon, 26 January 2015 12:50  |
appie
Messages: 902
Registered: April 2013
Location: denmark
Karma: 2
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Now my alternator lamp stopped working and I thought I have to fix that before we move on.
The light does not turn on with ignition. I guess it is some wire that got disconnected, but I am tryinh to understand how it all workes
Here i run in som problems, the handbook showes a 3 wire alternator, but installed is a 2 wire That I gave the apc wiring
I know my ignition switch is erratic and the po installed a seperate start switch
When I turn the ignition switch in the sysrt position the alt lamp comes on very bright. It also did this before i stopped working on ignition
I know I schould bring it back to original with a new ignition switch, but stil. It worked before, and I just like to understand
Btw. Alternator is charging fine
Appie
eleganza 76 "Olga" now sadly sold
6 wheel discbrake
Quadrabags
Springfield stage 2 462 olds
Manny tranny
( pictures at http://www.gmcmhphotos.com/photos/g6489-olga.html
Fulltiming in Europe july 2014 til july 2016
Denmark
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| Re: [GMCnet] Alternator lamp not working [message #271289 is a reply to message #270449] |
Fri, 06 February 2015 09:08  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Appie,
For a problem like yours, the wiring diagram is your friend -- far more
helpful than any one of us can be remotely. That's really a very simple
circuit -- the bulb just compares alterrnator output voltage with that at
the ignition switch (which is approximately battery voltage).
What you really need to consider is whether the 2-wire alternator is what
you should be running. Unless you have a combiner instead of the original
isolator, at least one of your battery banks is probably not being
completely charged. The OEM 3-wire alternator uses its "Sense" lead to
measure the voltage AT the battery ("downstream" of the isolator diode) to
regulate the output voltage. The 2-wire alternator uses it's generated
voltage internally to regulate its output, so it does not produce high
enough voltage to adequately overcome the forward voltage drop of the
isolator diodes. Under moderate usage, the 0.6-0.7 VDC under-charged
battery may seem OK; as it ages or load increases, its
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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