For future reference.
When testing the output of the trailer brake controller. The tbc will send a short pulse of power to check the resistance passing through the trailer to ground. If you use a test light it will see the pulse but the load is not high enough to activate the tbc. You need to draw somewhere around 2 amps for the brake controller to stay active. Then you can read the voltage while pressing the breaks.
One reason for the tbc not activating the trailer brakes or giving the "check trailer" message is bad break magnets. Typically you need to have at least two working break magnets (one axle) working for the tbc to work correctly. When i have tested them i hook up two break or turn bulbs in parallel to draw enough power to keep the tbc on. Then using my dmm i measure the voltage while someone else slowly presses on the break peddle. A 50 watt bulb or headlight bulb works too.
For those of you that have trailer break controllers that are not "compatible" with electric over hydrolytic breaks. Wireing a resister across the break wire to ground will allow the tbc to "see" the trailer. Somewhere around a 50 watt / 5 ohm should do it. You may need to adjust this depending on your particular trailer.
When testing the output of the trailer brake controller. The tbc will send a short pulse of power to check the resistance passing through the trailer to ground. If you use a test light it will see the pulse but the load is not high enough to activate the tbc. You need to draw somewhere around 2 amps for the brake controller to stay active. Then you can read the voltage while pressing the breaks.
One reason for the tbc not activating the trailer brakes or giving the "check trailer" message is bad break magnets. Typically you need to have at least two working break magnets (one axle) working for the tbc to work correctly. When i have tested them i hook up two break or turn bulbs in parallel to draw enough power to keep the tbc on. Then using my dmm i measure the voltage while someone else slowly presses on the break peddle. A 50 watt bulb or headlight bulb works too.
For those of you that have trailer break controllers that are not "compatible" with electric over hydrolytic breaks. Wireing a resister across the break wire to ground will allow the tbc to "see" the trailer. Somewhere around a 50 watt / 5 ohm should do it. You may need to adjust this depending on your particular trailer.