In this article the RV Repair Centre shows us how to replace a caravan's breakaway switch.
Caravans exceeding 2T gross trailer mass (GTM) are required by law to have a breakaway device. A breakaway device is an important piece of safety equipment that activates the caravan’s brakes if the caravan becomes detached from the tow vehicle. It can be easily overlooked because it may never be deployed in the lifetime of the van. However, if it is required you want to know it is going to work. It prevents the van from hurtling out of control into traffic or anything else in its path. It is an additional layer of defence in the event that safety chains fail to prevent the van from getting away.
So, how does a breakaway system work? Caravans have their own brakes because the brakes from just the tow vehicle are not enough to slow down the weight of a caravan safely. In normal driving situations the caravan’s brakes and brake lights are activated by an electrical signal when you put your foot on the brake in the tow vehicle.
The breakaway device is basically a switch that also sends an electrical signal to the caravan’s brakes and brake lights. The breakaway switch is a little box that is attached to the caravan A-frame. It has a pin inserted in it which keeps the system in the off position. The pin is attached to a cord which is connected to the tow vehicle. If the tow vehicle and caravan separate the pin is pulled out. This switches the breakaway system on and activates the caravan’s brakes and brake lights.
Some caravan manufacturers rely on the house battery to power the breakaway system. However, as this is a critical safety system the breakaway switch is often powered by a separate battery. In a previous DIY article (issue 630 in Caravan World and online here), we looked at how to test and replace this dedicated battery if necessary.
In this article, the RV Repair Centre shows us how to test and replace the breakaway switch if necessary.
 STEP 1 — If the breakaway system has its own battery, press the test button to check the battery status. This should be tested every time you use the van |
 STEP 2 — If the test indicates the battery is low, it may need replacing. If so, refer to our separate article on replacing a breakaway system battery |
 STEP 3 — If the battery is normal, continue with the test procedure below |
 STEP 4 — Locate the breakaway switch on the A-frame and pull on the breakaway cable in a straight line parallel to the breakaway switch box |
 STEP 5 — Remove the pin from the breakaway switch box. If the system is functioning correctly the brake lights and brake mechanisms should activate |
 STEP 6 — Check the rear of the van to see if the brake lights have come on |
 STEP 7 — If the brake lights come on it is a good indicator that the breakaway switch is working, but the brakes will need to be checked as well |
 STEP 8 — If the brake lights do not come on it is a good indicator that the breakaway switch is not working, but the brakes will still be checked as well |
 STEP 9 — Raise a wheel off the ground and try to turn the wheel. (Most people won’t have access to a hoist. Use flat ground, chock the wheel/s not to be raised and disengage the park brake) |
 STEP 10 — If you can rotate the wheel and the brake lights are not working the breakaway switch or an electrical connection to it is probably faulty |
 STEP 11 — Locate the breakaway switch wiring connected to the breakaway switch |
 STEP 12 — Cut the breakaway switch wiring leading to the breakaway switch |
 STEP 13 — Strip and join the breakaway switch wiring to bypass the breakaway switch |
 STEP 14 — Repeat the process of checking the brake lights |
 STEP 15 — Repeat the process of seeing if you can turn a wheel raised off the ground |
 STEP 16 — If the brake lights and brake mechanism now both function, the breakaway switch needs to be replaced |
 STEP 17 — If the brake lights and brake mechanism do not function, seek expert assistance for the wiring |
 STEP 18 — Disconnect the joined wires and remove the screw securing the breakaway switch |
 STEP 19 — Remove the breakaway switch |
 STEP 20 — This installation used the same screw to secure the earth wire and the breakaway switch |
 STEP 21 — Some sandpaper was used to clean up the corroded earth contact points |
 STEP 22 — Screw down the new breakaway switch. Be careful not to overtighten it so it is able to swivel |
 STEP 23 — Cut the new breakaway switch wires at a suitable length to connect to the breakaway switch wiring |
 STEP 24 — Join the new breakaway switch wires to the breakaway switch wiring |
 STEP 25 — Remove the breakaway switch pin |
 STEP 26 — Repeat the process of checking the brake lights have been activated to ensure the new breakaway is functioning correctly |
 STEP 27 — Repeat the process of checking the brakes have been activated and the new breakaway switch is functioning correctly |
 STEP 28 — Confirm the breakaway switch can swivel freely on the screw pivot point so that the pin is able to pull out when the car is turning if required |
 STEP 29 — Reinsert the breakaway switch pin |
 STEP 30 — Wrap insulating tape around the breakaway switch wiring |
 STEP 31 — Route the wires back into their original position |
If in doubt, consult a professional
Improper maintenance can lead to injury, death or property damage. Maintenance work of this nature should only be undertaken by people with suitable competence. The information provided is general in nature, not comprehensive and should only be taken as a guide. Individual discretion must be exercised and persons undertaking described tasks do so completely at their own risk. Publishers and creators of this content accept no responsibility for loss or damage.
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