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Charge Control Relay not working

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Charge Control Relay not working

Postby IsuzuCamper » Fri Jan 11, 2019 10:11 am

This is continuing from my system not charging. We have traced the issue to (what we believe) is the Charge control relay. Relay has been tested and appear to be working. When tested outside the vehicle it clicks. When back in the vehicle, relay does not click. No power is transferred through the relay. Trying to determine where the signal needs to come from. There is a white blue wire that goes to the alternator. Thick black wire is constant power. There are 2 smaller black wires that do nothing at the moment. Continuity has been tested between all the wires to from the alternator. All are good. Any thoughts. Taking a break. Full day of electrical fun.

Cheers,

Patrick
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Re: Charge Control Relay not working

Postby geeves » Fri Jan 11, 2019 1:15 pm

Clipboard01.jpg


essentially you need voltage at the IG terminal for the alternator to charge. The charge relay really only controls the light
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Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Charge Control Relay not working

Postby IsuzuCamper » Fri Jan 11, 2019 2:03 pm

Thank you Geeves. This is the info we were lacking. So the relay does not send a charge to the alternator? We traced a wire from the relay (white with a blue stripe) to the alternator. This is not the exciter wire. Basically we have one wire (black white ) with constant power, another (white thicker than the other white blue wire) that get power with the key on, then the small blue white wire, which after the connection is white red stripe. I've had the thing out 3 times now. I'm hoping I can find the "l" without another removal.

11 hours of electrical class today. Time for bed. Thank everyone.
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Re: Charge Control Relay not working

Postby IsuzuCamper » Fri Jan 11, 2019 2:18 pm

geeves wrote:
Clipboard01.jpg


essentially you need voltage at the IG terminal for the alternator to charge. The charge relay really only controls the light
Is the 1992 the same as a 1998? I see this is a bit newer diagram.
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Re: Charge Control Relay not working

Postby geeves » Sat Jan 12, 2019 6:08 am

essentially the same throughout the range
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Charge Control Relay not working

Postby DonaldNZ » Mon Jan 14, 2019 10:29 pm

The relay winding is driven by the alternator once it starts to charge,
if the relay is removed the alternator will still charge [if its the same as supplied diagram]


three small terminals on alternator

S = Sense 12+ live all the time, W/B white with blue trace although usually wiring diagrams white blue is written as W/L to avoid confusion with black. In Geeves diagram S is connected to battery via 50A fuse so the alternator knows how much to charge / regulator external battery reference]

IG = Ignition 12+ when key on, B/Y Black with Yellow trace, in diagram its connected to 15A Engine fuse along with normally open contact on charge relay. its purpose to the alternator is to turn off and on the regulator in the alternator.

L= Light outputs battery +, this when alternator has reached cut in speed and is charging, WG which is either white with green trace or might be grey trace. Its purpose is to extinguish charge [battery] warning light, change relay contact state to advise alternator charging, drive belt is ok & extinguish bulb test functions of other dash warning bulbs. some systems also use this to trigger a start inhibit when alternator running.

For testing of the alternator
confirm battery + to large B+ alternator terminal stud [I use one of a set of jumper leads for testing and battery to S & IG terminal and a 12v test light [with a 5w or less bulb] one end of bulb to battery + the other to the L terminal at alternator. The bulb will be on until alternator reaches cut in speed [say ~ >1200 alternator rpm]

Alternator L terminal is a good place to hook up + terminal [via a 1A fuse to protect the $150 regulator] of an engine run hour meter if required as it will only clock [add] time once engine started.
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