2000 Denali slowly losing power while driving

[Skweez]

Oops forgot to add anything when I hit post

[Skweez]

 

That's the best way to ensure a failure free alternator or starter these days.

 

In 2007 I bought an alternator for our '86 Grand Marquis. Should've kept that OEM one instead of buying this reman in hindsight ... but I got over 7 years out of it (OEM lasted 21 years). I still had the receipt when it failed, so I brought it, and the battery back to AutoZone - got a new alt., and got a few prorated dollars back on the battery. Bought a new battery from Interstate, and headed home. Not 2 weeks later, battery is FLAT. Not even 1 volt! So I charge it back up, and notice the battery light is on in the dash - key off, engine off! Had a bad diode in the regulator.

 

Tried to return it, but the dummies at AutoZone couldn't get the concept that just because an alternator CHARGES, doesn't mean it's GOOD. Excessive AC ripple will cause all kinds of problems on new vehicles today. Mine was just flat shorted.

 

Bought a used regulator on eBay for $14, and it's been fine ever since (3 or so years now).

That'll probably be the next step in getting this figured out if this BCM process doesn't work out.