Originally Posted by leered

My battery barely turned the engine (2012 T4R LTD) last Monday. Having this battery for over 3 years, I thought it's time for a new one ( bought one but didn't install because I wanted to make sure it is not the alternator causing this).
It turned out battery was only 60% charged . Charged overnight and passed testing the next day ( fully charged). However, I noticed my battery/alternator gauge is a little to the left from the mid line ( 14V) and using a voltmeter confirmed a 13.6-13.8V ( under the expected 14v+). Under load ( AC ON+ FAN @MAX+ HEADLIGHT ON) voltage at battery is 13.58V

Local AutoZone testing of the charging system showed PASS while O'reilly's test returned: REGULATOR FAIL then ALL PASS,.. REGULATOR FAIL.. then ALL PASS...then REGULATOR FAIL.. didn't help at all!

Just replaced the alternator with a Denso Reman and the voltage is 13.6V ( outside temp 99 F)- just like the OLD one!

On Vehicle NEW alternator test @ local O'reilly says REGULATOR FAILED. The old alternator PASSED the bench test ( at O'reilly ! This makes no sense, unless their diagnostic tool is bad .

With the old alternator, I've noticed in the morning ( cooler outside) the voltage is 14V+ while at noon or after driving a while, the voltage goes to 13.6V . Suspected a heat-related issue with alternator/regulator and trying to avoid getting stuck due to a near future alternator-issue, decided to replace it .

During the week I searched but I couldn't find any info on 5th gen T4R charging system. Today, one of the searches returned an article about Alternator Testing and it looks like the alternator output voltage is temperature-dependent. This means that my 13.6V at 99F (14.2V at 68F) is actually OK.

I'm hoping someone can confirm the normal voltage for the charging system . Could not find this or a diagram using Google searches ( at least not for 5th genT4R).

BTW, I've attached pics of the "PITA" rear bracket hoping it will come in handy for the next DIY-er I know I had a hard time just finding the bracket!

Note: I had to remove front/driver side tire to be able to see/access bracket /bolts.

Thanks !