First, my battery failed (has been slow cranking for almost 2 weeks) and my AutoZone lifetime remanufactured alternator hasn't been sounding good (failing bearings or brushes). I bought a new Duracell from Sam's Club (only batteries I buy for the last decade) and exchanged the alternator. Now my battery light (check charging system) is on when it wasn't before. I pulled the "new" alternator and had AutoZone bench test it, everything was good (including the diode, because I've had a bad diode before). I checked all the fuses for continuity and they were good. Any thoughts on why the light is on? It comes on after about 20 seconds of starting, so my thinking is it's a "system" check. I confirmed it's the 110 amp because I don't have navigation. I plan to drive to AutoZone today and have them "test the system".

Next question, I'm installing a led light bar. It has a wiring harness with relay and a switch with a red (off)/green (on) indicator light. It's made to connect directly to the battery, which means the indicator light is always on (red or green, and draining the battery). I want to tap into a "key on" source so there isn't the constant parasitic draw. I think I recall reading about "key on" sources being grounds, not + feeds, but I'm not sure. Any recommendations for a "key on" source, + or -?

 

Two updates...

1. I drove the truck to Autozone and had them "check" the charging system. Battery was good and alternator was charging, so they ordered me another alternator. Installed the 2nd new one this evening and no more light!
2. I did a little Googling today and found a reference for (+) key on/accessory wire info. I still have to confirm this, maybe this weekend, but here's the reference for everyone else.

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Last update, the black/light green wire in the steering column was the wire I needed.