I decided to upgrade my 1999 Jeep Cherokee Sport 4WD 4.0 with aftermarket LED headlights (z-offroad aftermarket headlights bought from amazon). I've installed lights on my diesel trucks with no problems but this is different. Before installing the right headlight that has daytime running lights and amber switchback features everything worked with no hyper flashing or dimness. After plugging in the "plug and play" portion of the light I took out the side marker light and cut off the connector and connected the female ends to a (green with yellow stripe wire and brown wire) to soon be connected to the aftermarket headlights. Before connecting the switchback and DRL features I turned on my lights without the jeep running and the LED low beams turned on no problem. I then decided to connect the DRL and switchback wires from the side marker (just like a video on YouTube showed to do) and I turned on the lights and hit the blinkers to see if the amber switchback worked and i got about 5 hyper flashes until both lights went out. I then turned off the jeep and turned it back on to just run the electrical and the blinkers worked for a little bit and the hazards worked for a little bit but eventually I lost all lights working including the dash. I then decided to call it quits and put the battery on the trickle charger over night so I could start fresh today with a new battery. Before I reinstalled the battery I decided to put all the lights back to OEM including the side markers and headlight. After that I decided to reinstall the battery and turn on the headlights. They turned on but slowly dimmed over a minute until they were almost gone. I read through the forum and decided to go get an EP27 flasher relay for LED's since maybe I blew that. I installed it and tried again but the same thing happened. I then decided to check every single fuse and relay under the hood and in the passengers side right foot floorboard and all the fuses / relays were good but I'm still having problems.

I am thinking I blew some sort of fuse or relay since the Cherokee worked perfectly fine before trying to add the headlight and I've returned it to OEM but I'm still not having any luck even turning on the car. I bought a new EP27 fuse since maybe the last one broke when I tried to start the Jeep but I'm afraid that when I try to start it again tomorrow it will have the same result.

Does anyone have any idea what might be causing this issue or what fuses or relays to check if you agree that it might be something along those lines.

Thanks for any help anyone can provide because I have no idea where to go from here.

Hey jw how this went for you and if you figured out a solution. I'm also trying to install LEDs on my 99 cherokee and I haven't started yet but I really want to get it right the first time lol

The EP27 fuse is what allowed me to put LED’s in my whole Cherokee from all the interiors using the one way light LED kit and then redoing the whole front to switchback LED’s and the tears to regular LED’s