That's a whole different animal. Charging system is very basic. Finding the gremlin can be a major issue.
Here's the basic charging wiring diagram and alternator connectors at the end of the post
But the questions aren't as simple
- Why was the alternator replaced? Dead? Over/undercharging?
- Was the battery fully charged and load tested?
- Was the battery light on or off before this happened?
- Did you measure for A/C leakage from alternator? Meaning the diodes are not properly rectifying from A/C to D/C. New or refurbished alternators aren't tested properly these days and QC sucks.
- Did you measure if while running there is a voltage difference between alternator output terminal and the reading at the battery posts (not the connectors and make sure you scratch the surface to get a good battery reading) Even 1/2 Volt not a good sign.
- Is voltage fluctuating?
- Have battery posts, terminals and extra wiring connected been checked and really well cleaned?
An outside good article on why this can happen:
Persistent Battery Light After Battery or Alternator Replacement
Here's a link to and old thread on testing but charging system is still pretty much the same basic system.
best way to test alternator
My suggestions:
Needed tools and products:
- Multimeter with A/C and D/C range
- Hand to wiggle wires and connections

- A can of electrical contact cleaner
- Vaseline
Check all of above questions off and ensure the answer is 100% yes.
Take off alternator plug spray both the wiring end and the alternator end with the contact cleaner. while off do a good visual inspection of the connector. Make sure the Main alternator output terminal is shiny and no corrosion. I would put Vaseline on it like one the on the battery terminals after connected even if it's covered by the boot. Check fuses and relay related to charging system including visual inspection for contacts in and out. Swapping then with another same one in the fuse box can sometimes help find a relay that SEEMS to work fine but has a little gremlin living inside causing intermittent issues. Problem clears and pops up elsewhere. If that ever happens stop and replace said relay immediately. No need to screw anything else up.
I'd suggest before doing anything to do the following skipping what you are 100% sure was done: Check for any DTC or pending codes. Clearing everything if any and disconnecting battery wait 10 minutes and start making sure everything is clean as a whistle. If battery not 100% fully charged do a slow charge. Max 2 amps till full charge. Then After all the cleaning, checking and reconnecting then you start her up and if light on start the test procedures listed.
Alternator connectors:
Diagram:
Just incase: Symbols
This should give you something to start with. Hope it helps.
Let me know if you need anything else. But be patient it takes me hours to find and even just to post.