When you turn your ignition switch on. Do you get a green light at your 12v signal wire on the dc to dc charger.
The charger will not activate unless you have 12v at the signal port. Also I have found that the 12v source must be using the same ground as the 12v battery input feed

Have you checked to see if you have 12v at the signal wire going into the dc charger. If you have 12v at the signal going into the dc charger but the green light is not active try using a jumper wire from the 12v positive cable going into the 12v input on the dc charger and run it into the 12v signal connection on the dc charger. If the green light lights up it means your other 12v source is not in the same ground source as the your 12v positive input cables to your dc charger.
I have run 3 - 40 amp Renogy dc to dc chargers in my motor home and Jeep. I found that the 12v signal source has to have the same ground source as the 12v power input cables to work.
I also recommend installing a 12v on/off switch in your 12v signal power wire going into the dc charger so you can turn off dc charger when you don’t need to charge.

Thanks for the suggestion. It had been working fine, so I don't understand why it would all of a sudden stop working the way it is currently wired. However, I am game to try any logical suggestions. I'll try wiring it to the positive cable coming from the alternator.

Also, the green light no longer lights up when the trigger has power.

Thanks for the suggestions. I'll let you know how it turns out.

So if your green light from the 12v trigger source does not light up anymore would mean you don’t have 12v on your trigger wire. Good luck