Electric trailer brakes are an easy to use and reliable way to control the speed of your combined towing rig as you travel. While they are extremely reliable, electric braking systems can have their issues. It’s important to know what those potential issues can be and how to deal with them in advance.
If you don’t, you can easily lose days of travel, be stuck on the side of the road, or quickly ruin a long-planned vacation. Worse yet, trailer brake failures can put you in a dangerous situation that could result in a serious loss of property, injury, or even death.
Here are some of the most common issues associated with electric trailer brakes and how to deal with them.
Can RV Electric Trailer Brakes Lock Up When Applied?
Electric trailer brakes can lock up when you apply them. The most common reason for electric trailer brake locking is having your boost settings set to high on your brake controller. If you are experiencing wheel lockup issues try decreasing your brake controller boost settings until the wheel(s) no longer lock-up. At that setting you are getting the maximum stopping power the brakes can offer.
If your brake controller offers preset based on specific trailer sizes or weights, then confirm you have the proper setting selected for your trailer. These settings alter how the brakes are applied. Selecting the wrong settings will provide less than optimal braking for your trailer and could cause lockup issues.
If these steps don’t solve the issue, then it is likely a mechanical issue with the brakes, a wiring issue, or a hardware issue with the controller. To rule out the controller, try towing the trailer using a different controller. If the problem persists then inspect the wiring and connections going back to the brakes.
If there is a short in the system which is preventing power from getting to one or more of your brakes, the remaining ones will be more prone to locking up. If all brakes are getting proper power then the issue is in the brakes themselves in which case, you’ll want to do a brake service and adjustment.
Why Are My Travel Trailer Brakes Locking Up On One Side?
Trailer brakes locking up on one side can have a couple of different causes. The most common issue is a lack of power from the brake controller to one or more of the brakes on the trailer. Starting at the hitch plug, inspect all wiring and confirm that good grounds are present at the brakes and that no shorts can be found. Check to confirm all the brakes are receiving proper power from the controller.
Once everything checks out with the electrical system then retest the brakes. If the issue persists then move on to check that the brakes are properly adjusted. Once the adjustment is complete if the issue persists then do an internal brake inspection to locate the issue.
Why Do My Travel Trailer Brakes Lock Up One Wheel?
A single wheel locking up on your trailer can be caused by several issues. The most common issues are poor maintenance, improper adjustment, or an electrical fault. To address the problem, start with an inspection of the brake and wiring leading to it. If you find any potential shorts (frayed wires, missing insulation, etc.) then correct those issues and retest.
You’ll also want to make sure all of your wiring connections are secure and not corroded. Poor connections can lead to a lack of power or poor ground which can both lead to braking issues. Once you’ve confirmed that the wiring is good and the brakes are receiving proper power then retest them. If the wheel is still locking up then check the adjustment.
Proper adjustment involves raising the wheel off the ground, removing the adjustment access plug off the back of the housing, and rotating the adjustment wheel with an adjustment tool or flat blade screwdriver until the wheel no longer rotates freely. Then back the adjustment wheel back off 10 clicks.
The wheel should now rotate freely with minimal brake rubbing. Always adjust all the wheels, not just the one having an issue. This will ensure uniform braking and will prevent the trailer from pulling to one side or the other while braking.
Why Do My Trailer Brakes Lock Up When The Lights Are On?
Trailer brakes locking up when you turn the lights on indicates a short between the light circuit and the trailer brake circuit. This can be translated to any situation where the brakes lock up when you activate another system. For example, if your brakes pulse with the left turn signal then there is a short between the left turn signal circuit and the brake circuit.
The correct this, start at the plug (truck and trailer side) and look for any corrosion, debris, or damage that could be shorting the trailer light pin to the trailer brake pin. If you find damage, repair or replace the damaged part. Corrosion or debris can be cleaned with an emery cloth and spray electronics cleaner.
If you can’t find the issue in the plug or receptacle then trace the wiring back to the brakes, looking for corroded connections, frayed wires, or missing wire insulation. Clean any corroded connections and repair damaged wires.
One exception to this rule is when using a wireless electric brake controller. Most wireless brake controllers get their brake activation signal from the brake light pin in the trailer hitch plug. If your wireless brake controller operates in this fashion then it cannot tell the difference between the brakes being activated and the hazards flashing. When the hazard lights are activated, the brakes will pulse with the lights. Due to the way the system works, there is no workaround or way to correct this.
Why Do My Trailer Brakes Lock Up When Plugged In?
If your trailer brakes lock up as soon as you plug them in then there is a short between your brake circuit and a 12V source somewhere in your system. To trace the issue down start at the 7 pin receptacle on your tow vehicle. If the indexing notch is at the top (12 o’clock), the trailer brake pin (pin 2 ) is at 5 o’clock and the ground pin (pin 1) is at 7 o’clock (the next pin over clockwise).
With the truck running and no brakes applied check the DC voltage between pins 2 and 1 with a digital multimeter. It should show significantly less than 1 volt. If it shows a voltage greater than 1 volt the issue is in the truck electrical system This may include an issue with the brake controller itself.
If the meter is showing much less than 1V, then have someone fully activate the manual bypass lever on the brake controller. You should see the voltage jump up to near 12V, when they release the lever it will drop back down to well under 1V. You can also have them press the brakes.
Depending on your controller and gain settings you may see the voltage jump up to something between 2 and 12V. If all these check out ok, then the truck is working correctly and the issue is in the trailer.
To address issues in the truck you’ll need to inspect and clean the plug receptacle pins, trace wires and look for shorts. To rule out a faulty brake controller you can swap out a known good controller if you have one. If you do not, you can consult your controller’s owner’s manual for a wiring diagram.
You’ll need to find the wire for the manual override signal, which is usually a blue wire. With a digital multimeter, test that wire to the ground. If it shows 12V at any time other than when the lever is fully activated then the controller is bad. Replace it and see if your lockup problem is resolved.
If you’ve narrowed the problem to the trailer side of things then start with the trailer plug. Inspect it to see if there is any corrosion, dirt, or debris that could be bridging power to pin 2 from any of pins 3 – 7. If there is nothing obvious, clean the pins as best you can and test to see if the issue is resolved. If it is not, trace your wiring and clean up any corrosion where wires join. Also, check the ground wires from the brakes to make sure they are clean and making good contact.
Finally, check your brake magnets. They do wear out and when they do, they’ll short to the drums and lock the brakes up. Look for wear spots worn by showing exposed wire. Replace any bad magnets.
How To Unlock Electric Trailer Brakes
If your brakes are locked up there are a couple of ways you can free them depending on the reason they are locked.
- If they are locked does to an electrical issue, disconnecting the cord from the tow vehicle will cut power to them and they will unlock.
- If they are locked up internally due to lack of maintenance, then you can try tapping on the outer housing with a hammer or mallet. The vibration may be enough to shake them loose and free them up. If that doesn’t work, try backing the adjuster wheels off while tapping on them with a hammer or mallet. If that doesn’t work then disassembly may be your only option. Even if you can get them freed without disassembly you should still do a complete brake service on them as soon as possible to prevent further issues.
- If they are locked due to over adjustment, back off the adjuster wheel at least 10 clicks. The wheel should turn freely with minimal drag on the pads. If it does not, continue adjusting back until it does.
- If they are locked up due to an internal failure like a failed part or broken pad then you’ll need to disassemble them and replace the affected parts. When you put them back together, adjust them properly and everything should work fine.
Why Are My Trailer Brakes Locked Up After Sitting?
If your trailer brakes are locked up after sitting, the most likely culprit is probably rust. Rust can form fairly quickly inside a drum brake, particularly in wet or humid environments. Activating the brakes periodically prevents the rust from jamming up the mechanism.
If you’re are experiencing this issue try tapping the housing with a hammer or mallet. The vibrations can break things free. If that doesn’t work, try turning the adjustment dials back until the pads break free. Tapping on them with a hammer may help free them up as you loosen the adjustment.
If that doesn’t work then complete disassembly may be required. Once apart, replace any unsalvageable parts and then properly clean, lubricate and reassemble. The brakes should operate fine after that.
Can Electric Trailer Brakes Be Submerged?
Electric trailer brakes can be submerged in water provided they are unplugged prior to doing so. If you leave them plugged in, the presence of water (especially salt water) can cause issues that could damage the brakes and/or the controller.
It is important to note that even unplugged, repeatedly submerging your electric brakes will greatly increase the chances of rust development in the mechanism and will generally cause more wear and tear on the brakes over time.
Why Are My Electric Brakes On My Trailer Making A Loud Noise?
Loud noises when your electric brakes activate are not normal. The noise could be one of several issues in the brakes including:
- Worn or broken pads
- Worn or broken springs
- Bad wheel bearings
- Damaged axles
If you can trace the sounds directly to the brakes, disassemble and inspect their internals. If you hear a loud noise, try to establish where it is coming from. The most common part failures include broken pads and return springs. These parts can make significant noise inside the trailer brake housing. To correct the issue, replace any worn or broken parts, reassemble the brakes and adjust them properly.