Battery light
Mountain Pass
Joined: Mar 2012
Posts: 234
Likes: 0
From: SoCal
Probably built-in voltage regulator on alternator. My battery light also used to flicker very occasionally, and I tied replacing both batteries, cleaning up the battery cable terminals etc., but it still flickered occasionally. Then one drive a couple of miles from home, it was more on than off. And once I saw the voltage gauge 3/4 of the way up stock analog dash gauge e.g. approx 17V? I was worried I might fry the ECM, GEM or IDM, so parked the X once I got home & replaced the alternator & no more battery light flickering since.
2 schools of thought when it comes to replacing - upgrading or replacing with stock rating style from a national branch with lifetime warranty and/or easy replacement.
I initially tried the upgrade path, by buying a 220A rated unit from DB Electrical, which ended up being worse in every way e.g. only 12.8V output at idle, 13.6V while driving & died within 6 months, so I wouldn't advise buying one from them.
When the DB Electrical alternator died, I was in a bind away from home, so bought a NAPA replacement with lifetime warranty (I think), and it outputs ~ 14.4 -14.5V at idle within a couple of secs of starting & when running & is still running fine so far, so I am happier now, though I would still entertain buying a higher rated unit (good for 15k lbs winch, comms radios & stereo with amp etc.), from someone like alternatorparts.com, though I saw someone mention in one of the threads on this forum that they had to make minor mods to their alternatorparts.com alternator or alternator bracket to get it to fit.
2 other points:
- I initially though the NAPA guy had given me the wrong alternator (i.e. the one for the gas truck instead of the diesel) as the alternator was marked with rated output @ 2100 rpm, but that is the alternator rpm, not the engine rpm, which is approximately 1/3rd i.e. 2100 alternator rpm / 3 = 700 engine rpm which is fine for a diesel at idle.
- ever since I had 2 alternators die on me in short order (i.e. the original & DB Electrical, NAPA still working just fine), I really like having a digital voltage gauge. I got this cheap Stinger one from Amazon ( ), and did the easy trick with popping the top cover off & covering the Stinger logo with electrical tape, so the logo isn't visible. They also make a blue illuminated one, but unfortunately not a green illuminated one to somewhat match the stock illumination. The gauge is small enough that it's easy to find a spot to put it that's easy to glance at, but is still somewhat out of the way so it's not too distracting at night. It's also useful for watching not only the alternator output, but also the battery level when the engine is off to monitor general state of batteries, especially if dry camping & running electrical stuff off the X, and also for watching what voltage the batteries dip to when starting the X.
2 schools of thought when it comes to replacing - upgrading or replacing with stock rating style from a national branch with lifetime warranty and/or easy replacement.
I initially tried the upgrade path, by buying a 220A rated unit from DB Electrical, which ended up being worse in every way e.g. only 12.8V output at idle, 13.6V while driving & died within 6 months, so I wouldn't advise buying one from them.
When the DB Electrical alternator died, I was in a bind away from home, so bought a NAPA replacement with lifetime warranty (I think), and it outputs ~ 14.4 -14.5V at idle within a couple of secs of starting & when running & is still running fine so far, so I am happier now, though I would still entertain buying a higher rated unit (good for 15k lbs winch, comms radios & stereo with amp etc.), from someone like alternatorparts.com, though I saw someone mention in one of the threads on this forum that they had to make minor mods to their alternatorparts.com alternator or alternator bracket to get it to fit.
2 other points:
- I initially though the NAPA guy had given me the wrong alternator (i.e. the one for the gas truck instead of the diesel) as the alternator was marked with rated output @ 2100 rpm, but that is the alternator rpm, not the engine rpm, which is approximately 1/3rd i.e. 2100 alternator rpm / 3 = 700 engine rpm which is fine for a diesel at idle.
- ever since I had 2 alternators die on me in short order (i.e. the original & DB Electrical, NAPA still working just fine), I really like having a digital voltage gauge. I got this cheap Stinger one from Amazon ( ), and did the easy trick with popping the top cover off & covering the Stinger logo with electrical tape, so the logo isn't visible. They also make a blue illuminated one, but unfortunately not a green illuminated one to somewhat match the stock illumination. The gauge is small enough that it's easy to find a spot to put it that's easy to glance at, but is still somewhat out of the way so it's not too distracting at night. It's also useful for watching not only the alternator output, but also the battery level when the engine is off to monitor general state of batteries, especially if dry camping & running electrical stuff off the X, and also for watching what voltage the batteries dip to when starting the X.
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