10si and the idiot light always on

CmuCmu said:

Hi, hope you're doing well. I recently rebuilt my alternator, a 10si. The original issue was that it was pushing 17 volts, so while replacing the regulator, I replaced the brushes, tridiode, diode carrier also. Checked bearings and winding. Confirmed it was only the regulator not working, but took the chance to replace those parts while we're at it.
So, reinstalled it, and it's working, but the idiot light is always on. With the previous regulator it was always off (literally thought that lightbulb was burnt or something).
What could it be? The alternator is working as intended with the proper voltage (13.4 to 15).

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Ricko1966 said:

What are the chances you got terminal 1 and terminal 2 flipped.

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CmuCmu said:

None, used the original plug as it was. Maybe? It could be backwards. Would it damage the regulator if I flipped the plug to test?

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Ricko1966 said:

No need look up wiring schematic for 10s1 1 wire goes to never mind I'll get the info and post it for you.

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Ricko1966 said:

Terminal 1 is the ground for the dash light. Unplug the socket,turn the key to run with a piece of wire ground Terminal 1 on the socket end,the light should come on. Remove the ground,the light should go off. Take a test light and a jumper wire. Still unplugged at the alternator jumper term 2 to the B+ Terminal hook your test light to the battery positive lead,key on engine off touch term 1 with your test light light should light, start the truck,touch terminal 1 again light should be out. If this does not test out,then you have an internal problem with the alternator,try putting the old diode trio back in. I suspect it's the problem.

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Ricko1966 said:

Terminal 1 is the ground for the dash light. Unplug the socket,turn the key to run with a piece of wire ground Terminal 1 on the socket end,the light should come on. Remove the ground,the light should go off. Take a test light and a jumper wire. Still unplugged at the alternator jumper term 2 to the B+ Terminal hook your test light to the battery positive lead,key on engine off touch term 1 with your test light light should light, start the truck,touch terminal 1 again light should be out. If this does not test out,then you have an internal problem with the alternator,try putting the old diode trio back in. I suspect it's the problem.

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CmuCmu said:

Alright, step by step:
Ground on socket: Light on
Removed ground: Light off
T2 to B+, testing T1: Light on (and same volts as battery)
With engine on: Light on

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Ricko1966 said:

If you have a jumper from term 2 to b+ and
the test light is on ,while connected to battery,and term 1 with the engine running. Your alternator is not functioning correctly. The test light should go out with the engine running. I'd put the old diode trio in and check again. If no change, I'd put my old regulator back in and see if my light went out. If my light went out with the old regulator but I had an overcharging condition I would assume my new regulator was bad.

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CmuCmu said:

Alright, I'll get to the tridiode tomorrow and post results, glad I kept the old one since it didn't have any issues during testing; however, if I were to use the truck, what could happen if this issue isn't corrected?

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Ricko1966 said:

If you have a jumper from term 2 to b+ and
the test light is on ,while connected to battery,and term 1 with the engine running. Your alternator is not functioning correctly. The test light should go out with the engine running. I'd put the old diode trio in and check again. If no change, I'd put my old regulator back in and see if my light went out. If my light went out with the old regulator but I had an overcharging condition I would assume my new regulator was bad.

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