Troubleshooting Brakes on 1986 Prowler Travel Trailer that Cut Out Intermittently

Question:

Hello I have a 86 prowler travel trailer I recently purchased and couldnt be more happier with how good of shape its in. The only issue Im having is the brake connection cuts in and out on the highway. The trailer lights stay on consistently. Im sure I cant be the truck its 2013 f150 with a factory tow package and brake controller. I opened and checked the wiring connections in the access panel under the front of the camper and replaced the old splices. Im kinda of stumped the only other thing I could think of is a bad ground somewhere but wouldnt that make the lights not work? Also when the connection to the brake is on the gain has to be very high in order to feel the brakes even a little bit. And info is greatly appreciated and look forward from hearing back.

asked by: Andrew F

Expert Reply:

Since your trailer lights appear to behave normally but your brake circuit cuts in an out, I would focus on the trailer brake circuit wiring. Your trailer brake wire could have a crack in its insulation, or rub against part of the trailer frame at highway speeds due to vibration. Either of these circumstances could cause an intermittent short that takes out your brake power. Given the ages of the vehicle and trailer I would start troubleshooting the trailer's wiring as it is more likely to have the problem, as you noted.

Start at the 7-way plug on the trailer; inspect its contact surfaces carefully for any signs of even slight discoloration on the brake circuit contact (see photo, please). Follow the wiring back to the junction box (if one is present) looking for loose or corroded connections, worn or cracked insulation, etc. Continue following the brake circuit wire back to the individual brake assemblies. You may only need to replace the 7-way plug with an item such as # H20046. If so a junction box # 38656 and ring terminals # 44-5310A make this easier. If you need new brake circuit wire use # 10-1-1.

If your brakes totally cut out all at once chances are that the issue is upstream of the brakes themselves but you can still check the hot and ground connection at each individual brake. You can also easily test each brake by bypassing the trailer wiring and applying 12V power from the vehicle battery or a spare direct to the wiring of each brake. You should be able to hear a gentle humming from the brake when energized and also naturally feel the brake drag on the drum.

Please let me know what you find during your trailer inspection.