Alternator light dim

[larryxp]

Just replaced external regulator with new O Reilly unit due to battery(new) draining problem. Alternator bench checked ok on their tester. The alt warn light is now staying on in a dim state. Per instructions I found here at various posts,I checked for voltage on back of alternator (key off) and at green/red wire on regulator (key on), had 12 plus volts both places. Cleaned regulator mounting areas and reg gnd wire terminal. Checked voltage across battery, it is 12.6 engine off, 13.5 engine at idle, 14.2 engine well above idle (appx 1500 rpm). Can anybody tell me why light is now staying on, I could not find any posts that dealt with this. Thanks, Larry

[70_F100]

It sounds like you may have a failing diode in the alternator.

Sometimes this will not show up on a bench test.

[Thunderfoot]

I would take the Regulator back and get another, Many have had problems with "NEW" regulators being bad in that the alt light stays on even though it is charging fine. The alt light is controlled by the Regulator.

[larryxp]

Thanks for advice. Took regulator back, traded for another on warranty, wasn't even very painful. Light is now off. Thanks again, Larry