We need a little more info to try and help better. You may have more than one issue going on at a time.
What year is the camper? Make and model?
Not sure if you are the original owner or not; any idea how many towing miles are in it?
What brand and model brake controller do you have?
When you stated you appeared to have corrected the issue, then after some time passed into towing once again, the brakes stopped working. What told you the brakes were not working in "all" the times when they stopped working? Did the brake controller flash, if the brake controller had no errors; you could not feel the brakes working, etc.? We need more info on how you knew they were working and when they were not working.
Here are some big-picture things that "might" be going on. Any and all may be going on at the same time.
The melted breakaway switch, these switches do go bad over time. Water gets in and corrodes the contacts making them fail in a few ways.
- The pin can get frozen in place as the O ring dries up, and it feels like it jams the plunger in.
- When the contacts corrode, and the pin is pulled, the resistance in the switch is very high and starts creating a lot of heat, and, in some cases the switch melts.
- The contact corrosion can sometimes corrode the contacts together if it is bad enough, with the plunger in place. This allows the power to be on a lot of the time and since the connection has high resistance, it creates a lot of heat for a long time and might be what melted your switch.
- The 3 above are the more common failure modes; I'm sure there are more. If you read the directions on these switches, many brands state to replace them every 3 to 5 years. The breakaway is a forgotten safety device. I have seen many campers 10 to 20 years old still with the original switch.
While you changed the switch, the braking problem still seems to be happening. As I stated, you may have more than one problem at the same time. Yes, the breakaway switch was bad, but there can be more.
1. As the other poster stated, check the 7 wire brake plug/connection. Clean up all the contacts. It is common that corroded contacts can make and break as the truck bounces down the road or the cord is pulling from not enough clearance in a turn etc.
2. You may have the classic old camper worn wire inside the axle tube problem. As the camper gets older with higher towing miles, the wire inside the axle tube is chaffed bouncing down the road. The hot wire or ground wire can have the insulation worn clean through to the wire. When the hot wire touches the tube, and you apply the brake power, it shorts the brake coil from getting any power. This comes and goes depending on how the worn wire lands in the tube.
3. You have bad brake connections in the wiring in the camper. It can be the ground wire not making contact. While the hot wire gets looked at a lot, losing ground will stop the brakes from working also. In this case, if you lose the DC -, (ground), in the 7 wire cable where it attaches to the camper, the camper frame lost ground or any other grounding place all the way to the brake coils.
4. If the breakaway switch was partly on for a long time when it failed, the brakes had some level of power going to them for a long time while towing. After you check all the wiring as stated above, you may have to pull the brake drums and look inside for mechanical issues. There are many issues that can happen inside, maybe not all 2 or 4 brakes at once, but if the breakaway was sending power for hours on end while towing, something could be wearing at a higher than normal rate.
You stated, it seemed like when you pulled the new breakaway switch pin and reinserted it, the brakes seemed to start working again. This may just be a coincidence, it is not the cure of your problems. Applying full power and then removing it, cycles the magents and can wiggle the magnet arm. This wiggle action may free up a brake that was partly tight being engaged when you stopped. The event was temporary and random.
Older campers have the above more frequently than newer ones, but not always.
Hope this helps
John
