2012 Jeep Liberty Headlights Cause My Trailer Turn Signals and Brake Lights to Fail

Question:

I bought the Blazer LED submersible trailer lights for an old trailer. Wired everything correctly for about and an hour and a half and got nothing. So I took a grinder to the ground spots and the good lord said let there be light! I now have dim running lights as soon as a connection is made. And when the lights are on on my 2012 Jeep Liberty the lights are full on. However I do not have brake lights or turn signals now. Im still using the old rusted bolts and nuts, but the wire is touching freshly grounded trailer metal. What do you think the issue may be? HELP!!!

asked by: Tyler C

Expert Reply:

It sounds like there may be a couple of issues going on here. First, It is very common for LED lights like # C7493RTM & # C7483RTM to remain on very dimly whenever the trailer is connected to a vehicle, even if the ignition is turned off. The only solution is to disconnect your trailer when you will be parked for extended periods.

Now let's address the bigger issue. When turning on the vehicle's headlights causes one or more of the trailer lights to stop working the number one culprit is an insufficient ground or short to ground on the trailer or the vehicle side.

You mentioned that you verified that all of your grounds on the trailer were good when installing the lights. You will also want to check the trailer wiring for any fraying, splitting or corrosion that may be causing a short. I've provided links to Parts 1 & 2 of our Finding and Fixing Wiring Shorts video. Sometimes, even using a plastic license plate frame instead of a metal one behind the left tail light could cause a ground issue. I've also attached a link to a video on proper testing for a good ground connection and our installation video for the lights you purchased. You might take a few minutes to watch them and see if anything was missed when you completed your install.

The next thing to check is the vehicle's wiring. I've provided a link to instructions for troubleshooting your vehicle's harness. If you don't have one on hand, you will need a circuit tester like part # PTW2993 to make sure that the wire connections have been properly made at the taillights.

If all of that checks out fine, then the second most common culprit is that the harness is overloaded when the taillights are engaged because the trailer has too many running lights. Since you converted to LED lights which have a very minimal power draw, this should not be the issue unless you also added additional running lights.

Once you've checked both your trailer and vehicle wiring, let me know if you are still having an issue. I'm sure we can get to the bottom of it.