Can someone share how to test a volt regulator? I have a 82 xj6 series 3, are the volt regulators inside the alternator or outside? My battery warning light has been on, alternator test from autozone and oreillys both pass but battery failed. Replaced the battery but warning light still stays dim. Is there a way to test the dummy warning if thats just the problem? Belt is tightened on alternator, is there anything else im missing i should look for? thanks

 

how exactly did autozone test the alternator if it was not off the car ?

by connecting a tester to the battery poles?

that's not an alternator test in my book.

 

Jose:


Yes and no. Way back when, I was working in a full service gas station while going to TWC, now known as UTEP! My boss was learning about and using equipment to test regulators for the generators in the cars at the time. Simple electromechnical devices similar or the same as the relays that are found in our Jaguars. By test and bend, one could diagnose and at times fix them. The meters were volts and amps and the guide as to how to connect them.


So, yes, an alternator is best tested at the connectors within or at least at the out put.


But, at the battery posts, one can get an idea as to what is going on, if anything by the alternator. Mere voltage comparison, engine off versus engine on!!!


I found that by making a patch cord to connect my VOM at the cigar lighter, I could read volts at various loads and rpm's in real time.


And, a very "rough and ready" of the past was by observing the hard lamps and revving the engine. Get brighter? More volts?


Carl

 

Reading at the post is actually not a bad idea as it shows what voltage is
being presented to the battery for charge recovery. Reading from the post
as opposed to the cable terminal adjacent to the post is best because it
eliminates any voltage drop from a loose or corroded connection.

Start by reading voltage across alternator output and ground. It must be
somewhere between 13.8 and 14.8 for reliable battery charging. If that
is not achieved, start looking. If that passes, then take a reading between
the battery posts. If there is more than a 0.1 volt difference, start looking
for voltage drops along the charging circuit keeping in mind that the circuit
is formed by both the postive and negative paths.

Take a voltage reading with the AC scale of the voltmeter. If a significant
reading is shown, suspect the rectifier bridge.

Take readings with ignition off at the alternator to check for leaky circuits
that point at the regulator, diode bridge, stator, rotor depending on the
location.

All of the above is explained in detail step by step in various tutorials that
can be found elsewhere. The above just shows how useful a voltmeter can
be in electrical diagnosis.

 

Tommorow im going to grab a voltreader and start testing. Im suspecting its a faulty warning light. Im going to take the dash off and test the light. But how exactly do I test it if it stays on? How would I go about it?