Do It Yourself home repair & maintenance am replacing a fluorescent light ballast and need some electrical advice.
It is a 4′, 4 bulb fixture and I am swapping out electronic ballast. The light doesn’t come at all at times and I have already confirmed it has new bulbs and 120v incoming power from the light switch.
The question is, the new ballast has two yellow wires w/ a black and white wire on the opposite side of the ballast that has the other connector wires. The old ballast had one yellow wire connecting to all four bulb connectors. Should I leave one yellow wire disconnected or does it need both of them to function properly? If both need to be connected, how should it be done? This is the only thing I am stuck on, otherwise I believe I can swap the ballasts. I will try to complete this job today.

It depends on the ballast. They are not all the same. Forget about the old ballast. It was wired differently than the new electronic one. Just carefully follow the wiring diagram on the ballast.

Don’t forget, you must use T8 lamps with this new electronic ballast. You CANNOT use the old school T12 lamps.

I did rewire the fixture with the new electronic ballast, that had two yellow wires going to one end of the bulb connectors. I just clipped the daisy chained connector wire in the center, which separated them into two connected pairs. Then I ran one yellow wire to each pair of bulb connectors.
Other than that, using the new ballast wiring diagram,on the opposite end of the fixture,I twisted each of the connector wires together, red w/red, blue w/blue, gray w/gray, brown w/brown, then connected the (4) two red/two blue electronic ballast wires, one to each twisted wire connector.
The fixture is now working fine with the new electronic ballast.
I appreciate your knowledge and assistance.