Help: Dim Headlights and Auto Lights Switch Not Working

[RXB]

2008 RX 350 FWD Symptoms:
After jumping engine with battery booster (Batt was dead not sure what drained it overnight - Had alternator replaced about 3 months ago):
1) It was early morning and still very dark, the low beam headlights did not come on and light switch was on auto.
2) High beams worked fine.
3) When I moved light switch to manual the low beams came on but very, very, dim.
Appreciate any trouble-shooting suggestions
Many Thanks

 

[NXracer]

Could be as difficult as a blown DRL module or simple as a battery/alternator going out. If you have an MNC auto chain they do free testing for the battery, alternator, and Check engline lights. Do all three and report back; simple stuff done.

After that, while jumping the vehicle, any weird events like cross polarity or etc? You would need to trace wiring diagrams for the headlight circuit.

 

[RXB]

I had the alternator replaced in early January of this year. AAA and the mechanic both verified the alternator had to be replaced.
What is a DRL and where is it located? What is MNC?
Next I will check the door switches, if one fails it sends a signal that a door is open and the headlights remain on and drains the battery. Other than that I'll have to look for a parasitic drain on the electrical. That is pretty time consuming.
Thx

 

[NXracer]

Daytime Running Lights=DRL
I'd search and post on an RX specific thread board to find the location and more troubleshooting info

Multinational Chain=MNC like autozone or AAP