Today Im going to show you how to test the functionality of a trailer four-way connectors. What youre going to need to do this is a circuit tester and a buddy in the drivers seat to operate the taillight functions. The first thing were going to test is the taillights themselves. Hit the taillights. (beeping) that means thats working. The next thing were going to test is the left blinker.
(beeping) That works. Then were going to test the brake light function on that side as well. So, hit the brakes. (beeping) That works. Then for the right blinker (beeping).
Now the right brake (beeping). Now we know that this four-way connector is functioning.
Kenny
8/23/2020
I just installed the Allen’s tailgate led light bar. I have brake, right/ left signal and hazard lights. The only function not working is the running lamps when the lights are on at night, they are off unless I brake or signal. I checked for blown fuses and all were good. I checked the trailer park fuse in my 2002 f150 and it was fine but I replaced it with a new one anyway and still no luck. Everything works except for the running light mode. What gives? Maybe a loose ground? Where do I find that?
Jim
3/16/2014
What if the brake lights function but the turn signals dont? 2004 Chevy Blazer. Tail lights and brake lights working properly but turn signals are not.
Daniel S.
12/3/2020
Thank You!!! fuse was blown but it made me in the begining clean neg connection then check fuse...wallah....done...