Trailer Right Turn & Right Brake Lights Do Not Work After Installing Wiring Adapter # 37185  

Question:

Expert Reply:

Both trailer right turn and right brake light signals are carried on the same wire, a green wire in the case of the Hopkins adapter # 37185. Since these are the only functions not working I suggest you first test the green wire on your Jeep's 4-pole harness, the harness that plugs in to the Hopkins adapter. You'll want to look for signs of discoloration or corrosion on the contact pin for the green wire; clean as needed. If you have a circuit tester like # 40376 you can test that pin while a helper engages the right turn and brake. Please see the linked video.

If you do not detect the correct signals on the 4-pole then you might check that the Jeep's wiring harness main ground wire is firmly secured to a clean bare metal surface that is free of grease and dirt. You can also make sure the connectors for the harness, such as # 118409, are fully seated to the connectors on the Jeep taillights. Check for a bent or damaged contact on the passenger side connector. If the signals are present on your 4-pole then move downstream to the adapter and test the pins on the 7-way.

You can also test the trailer lights directly by applying power to the circuits on the trailer 7-way plug for those functions. Please refer to the linked photo that shows you the usual configuration for 7-way wiring on a travel trailer or camper. You can use the Jeep battery or a spare to apply power directly to the trailer; if the lights work when powered in this way then you know the problem is upstream of the trailer wiring. You can also check for any blown fuses in the power distribution box in the Jeep and replace as needed.

expert reply by: Adam R

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