I have a duo therm brisk air model 57915-001 leak

First thing I will say is to check run-off from AC unit on roof, as in, is it still draining good across the roof and dripping out of gutters? If it's still draining off roof good, then plugged drains probably not the problem. With that said, if not draining well, On that system, you need to go on roof and remove plastic cover (power off inside) and go to front end where you will see short philips screws holding front metal cover over evaporator. Remove all the screws and carefully remove cover trying to be careful not to destroy gasket at edges. Now with that off, look down at foam tray at bottom and you will see where condensation tray is formed to catch water and redirect it out. It runs along back, sides and front like a little channel to redirect water outside the unit. About half way forward on sides, the drains which are hard to see direct the water out the holes at base of AC unit. The entire channel/tray needs to be free of any debris that may plug those holes on the sides. I use an airline with long air nozzle to blow it all out clean, then concentrate the air pressure down low at sides where drains are to blow out any debris that may be obstructing flow. Takes a little work to get to those drains but when clean, water should flow back on to roof good, and dripping in to trailer should be fixed. Take time to vacuum fins at front as well when you have that cover off for better performance. Use a soft bristle brush attachment so as not to bend fins too much. If it is draining good off the roof and water is dripping inside, take a flashlight and look way up inside at coils and fins at front of unit with ceiling cover/filter off, and you'll likely see a fair amount of dust and debris on the coils/fins. With some extensions on vacuum, you can vacuum fins from inside as well. First thing I will say is to check run-off from AC unit on roof, as in, is it still draining good across the roof and dripping out of gutters? If it's still draining off roof good, then plugged drains probably not the problem. With that said, if not draining well, On that system, you need to go on roof and remove plastic cover (power off inside) and go to front end where you will see short philips screws holding front metal cover over evaporator. Remove all the screws and carefully remove cover trying to be careful not to destroy gasket at edges. Now with that off, look down at foam tray at bottom and you will see where condensation tray is formed to catch water and redirect it out. It runs along back, sides and front like a little channel to redirect water outside the unit. About half way forward on sides, the drains which are hard to see direct the water out the holes at base of AC unit. The entire channel/tray needs to be free of any debris that may plug those holes on the sides. I use an airline with long air nozzle to blow it all out clean, then concentrate the air pressure down low at sides where drains are to blow out any debris that may be obstructing flow. Takes a little work to get to those drains but when clean, water should flow back on to roof good, and dripping in to trailer should be fixed. Take time to vacuum fins at front as well when you have that cover off for better performance. Use a soft bristle brush attachment so as not to bend fins too much. If it is draining good off the roof and water is dripping inside, take a flashlight and look way up inside at coils and fins at front of unit with ceiling cover/filter off, and you'll likely see a fair amount of dust and debris on the coils/fins. With some extensions on vacuum, you can vacuum fins from inside as well.