1. Failure in electric fence systems, that have been working is almost always found in the failure of the charger or the failure in electrical connections including the ground rods. Keep in mind that severe loss of ground moisture can radically affect the flow of fence power. A sequence that can be used to trouble shoot fence failure is as follows.
2. Disconnect the fencer from the fence and test the power across the positive and negative posts. A five light or, better yet, digital tester should be used for this test. A full positive charge does not always indicate that the charger is working properly. It may be failing to develop enough power to overcome normal fence load but shows adequate power on the tester. Testing the charger first will eliminate the possibility of complete charger failure. Do not use an ohmmeter to test fence charger power as the extreme output of the charger will damage an ohmmeter.
3. Walk the fence line looking for broken wire on the ground, or cracked insulators allowing wire to touch posts or broken connecting wire. Also look for larger weeds or broken tree branches touching the fence.
4. Check the ground rod connections, taking them apart, cleaning and reconnecting.
5. If all seems in good order start testing the fence power close to the charger and in increments of 40 to 50 feet out to the farthest point from the charger. If the power is good close to the charger and declines to a point of dysfunction, the farther away you get, you may need more ground rods or the fencer is failing to produce adequate Joules to maintain fence power. Try another charger. Keep in mind that a strong fence in the spring may be week in the summer due to declining ground moisture. If this is the case you may not have a strong enough fence charger to work year round. You may also need to upgrade to a hot ground system or install a ground wire to the farthest end of the fence with additional ground rods at that point.