Chg and brake light

[Zed Head]

There are several ways around this.  Do you have a meter?  You can start the car and see if the alternator is charging.  Measure voltage before starting the engine and after starting it.

You can disconnect the T plug and see if you have continuity to ground on the L terminal of the alternator.

More clues.

[AZDatsun]

Yes I have a meter with my car off the voltage was 12.75 across battery terminals with it on at idle it was 13.45. I pulled the t plug with the car off and moved my meter to ohms when I was on the blue wire and a ground point it showed 0 ohms


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[Zed Head]

So, with the key on and the engine off, the charge light is not lit?  It's not common but the lights do burn out.  The charge light should light when you turn the key On then go off when the engine starts.

Not sure how that relates to brake light staying on, the original problem.  It's hard to dig in to electrical when it's not in front of you.  And it's not yours.  Sounds like you are operational though.  Maybe someone else will take a crack at the puzzle.

The wring diagram shows two circuits connecting to the L wire.  So, maybe you lost one circuit through a short or a fuse, but still have one to keep your alternator charging.

[Zed Head]

1 hour ago, AZDatsun said:

Yes I have a meter with my car off the voltage was 12.75 across battery terminals with it on at idle it was 13.45. I pulled the t plug with the car off and moved my meter to ohms when I was on the blue wire and a ground point it showed 0 ohms

I notice that you said "on the blue wire", not on the alternator terminal that connects to the blue wire.  Not sure what exactly you measured.

Probably a good time to put a check list together showing each thing that you did and the results.  There's quite a few actions and results in the thread now.  A list will make things clear.

[AZDatsun]

Before I go back do you want me to pull the T plug with the battery connected then put my meter where the blue line was connected and to a ground to measure ohms?


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[Zed Head]

That would be good to know.  Do that with the engine not running, just to see if the circuit through the alternator is good.

[AZDatsun]

Ok car off and battery connected t plug unplugged and ohm meter on 20k I get 1.59 ohms when it’s connected to where the blue line was on the alternator and a ground


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[Zed Head]

That seems about right.  Are you sure that the Charge light does not come on when the key is turned to On?

[AZDatsun]

Yes double triple checked the light although maybe it burned out whenever that event happened I will swap it out


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[AZDatsun]

Well I am going to walk away with my tail between my legs swapped the bulb and it’s working with key on and when I start the car the light goes off.. so whatever happened on that drive burned that light out because it was working I guess that will remain a mystery.. thank you all for everyone’s help in this




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[Captain Obvious]

Great! Glad to hear at least part of the problem was a simple fix.

So are you "whole" now, or is the brake warning light still giving you troubles when you put the relay back in?

[AZDatsun]

Everything is all good now. I am not going to touch anything and not go to that intersection again is the best course of action right now.


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