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Old 10-19-2018, 06:45 PM   #1
65truckowner
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gen light

I cant get my gen light to work on my 65 c10. When I turn the key on and test it with my test light it lights up but I cant get the bulb to work. It is a plastic socket so it does not ground to the cluster.. I have changed the bulb three times also
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Old 10-19-2018, 07:36 PM   #2
ray_mcavoy
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Re: gen light

One side of the bulb should have a pink wire that connects to the ignition circuit. It applies battery voltage to that side of the bulb when the ignition switch is in the "run" or "start" position.

The other side of the bulb should have a brown wire that runs out under the hood and connects to the #4 terminal on the voltage regulator. Or has been re-routed to the appropriate "light" terminal if it's been swapped over to a newer style internally regulated alternator.

When the alternator is not producing power (such as with the key on / engine off, or an alternator problem), the voltage regulator (either external or internal) provides a ground on the brown wire that completes the circuit and turns on the "gen" light. Then when the alternator is producing power, there is voltage present on the brown wire (equal to the voltage on the pink wire) so the "gen" light turns off.

So check to be sure there is battery voltage present on the pink wire with the key on. And check the brown wire to make sure it has continuity all the way from the bulb socket to the voltage regulator.
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Old 10-19-2018, 08:50 PM   #3
65truckowner
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Re: gen light

The brown and pink both lite up the test light with the key on so sounds like the brown wire has problems. I will check tomorrow. Thanks for you reply
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Old 10-20-2018, 07:00 PM   #4
65truckowner
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Re: gen light

Ok got the gen light working but now I cant get my new alternator to charge. I double checked the wires to make sure they where hooked up right, then changed the voltage regulator still nothing. What else should I check???? Maybe a bad new alternator?
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Old 10-22-2018, 05:18 PM   #5
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Re: gen light

Alternator was bad the parts store ordered me another
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Old 10-23-2018, 06:17 PM   #6
Broken65
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Re: gen light

I've been lurking these threads for months as I work on my 65 truck.. I've come into a problem that's been puzzling me for over 6 months and I've decided to ask. My brown/w #4 terminal wire is not getting power from the ignition to the voltage regulator. it has power at the instrument cluster and the ignition, but is not sending it from the dash to the voltage regulator.. The voltage regulator is grounded well as is everything else on the truck, it has +12V on the large red wire. All wiring is done per the 1965 diagrams. Any help or clues is appreciated....
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Old 10-23-2018, 08:54 PM   #7
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Re: gen light

Quote:
Originally Posted by Broken65 View Post
I've been lurking these threads for months as I work on my 65 truck.. I've come into a problem that's been puzzling me for over 6 months and I've decided to ask. My brown/w #4 terminal wire is not getting power from the ignition to the voltage regulator. it has power at the instrument cluster and the ignition, but is not sending it from the dash to the voltage regulator.. The voltage regulator is grounded well as is everything else on the truck, it has +12V on the large red wire. All wiring is done per the 1965 diagrams. Any help or clues is appreciated....
Welcome to the forum.

Why in the world did you wait six months?

Lets take a look.

Here is your diagram looking at the top is the ignition switch and the 24 gauge brown/white stripe wire for power to the regulator.
Follow it down to the forward lamp harness connector in your firewall.



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It comes through the forward lamp harness connector as a 20 gauge brown wire and goes to the regulator no. 4 terminal.

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If you have power at the ignition with the key on, and you have power at the gauge cluster, (you must have the light dash and not the gauge dash like the diagram). Then the wire from the light must go to the forward harness connector and join with the brown/white stripe wire from the ignition, and then go through the connector to the regulator.

Name:  ChevyC101965-EngineHarness-COLOR.jpg
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I would suspect that you have a bad connection at the forward harness and lamp connector, between the B/W stripe and the brown wire from the charging light, and the brown wire on the engine side of the connector.
If you have the gauge dash with the ammeter then you won't have the charging light and the diagram will look like the one above.

If you have the charging light then the diagram will look like this one.


Name:  64_wiring_page2.jpg
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Notice the brown wire from the cluster light joining the B/W stripe wire at the fwd harness connector.
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Last edited by VetteVet; 10-23-2018 at 09:01 PM.
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Old 10-23-2018, 11:45 PM   #8
Broken65
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Re: gen light

It took a while due to working on multiple issues, I'm just getting back to this after having the carb rebuilt.

I do have gauges. The second picture is the wiring I have, though I've never seen that diagram.

I notice the b/w wire from the forward harness to the horn relay "BAT" tab. I don't have that on the truck and didn't know it needed one. I did discover the b/w inside the cab and it is correct until it reaches the forward harness. So I'll add that tomorrow..

I have another question about the voltage regulator. There is the F #2 #3 and #4 tabs, but what is the side tab for??

Thanks for the help so far!
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Old Today, 04:47 PM   #9
stellar
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Re: gen light

It is for a condenser
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