Any advice on a cheaper and effective way to replace the headlight ballast without spending $2000? I have read about some oem parts but I’m skeptical about how long they last. Accepting all advise you all can spare. Is this any good?

OE-PART: Replacement HID Ballast for DENSO KOITO D4S D4R DDLT003 35W

 

 

Likely got water in it. That said, Generally it is the bulbs that are failing, not the ballast. You try swapping bulbs from side to side?
If it's a bulb, these are good.