Brake lights working but Prodigy says not connected

aubiexx wrote:
Thanks. If I use a voltmeter to test the electric brake connection on the receptacle on rear of my tow vehicle, should it register amperage when the brakes are pressed and my tail lights are on?

When it comes to the Prodigy P2 and P3 there is a lot of confusion on how the controllers work. Pressing the brake pedal does not always send voltage to the trailer like the time based units do.

If there is no boost programed in there will be no voltage to the trailer when brake pedal is first pressed. But if the brake is held for more than 5 seconds the Prodigy will send 25% of the gain setting to the trailer.

If Boost 1 has been programmed the Prodigy will send 14% of the gain setting then after 5 seconds 25%. If boost 2 or 3 the initial will be 28% then after 5 seconds 25%.

Moving the slider will always send voltage to the trailer. Full travel will be what ever the gain was set to.

When the TV and trailer are moving and the brakes are applied the Prodigy will first send the Boost setting voltage then it will send a voltage that is proportional to the deceleration rate of the TV and trailer. This can be anything from 1 volt or less to the gain voltage depending on how rapidly the TV and trailer are decelerating.

Here is a link to the instruction book.

Prodigy P2 Instruction Manual



Now to answer your question yes a voltmeter can be used to measure the voltage but not amperage at the 7 way connector. Due to the Prodigy using a pulse width modulated voltage you may not see the same voltage as the Prodigy display.

But the prodigy will put the gain voltage value to the 7 way when the slider is moved to max travel. This is even when the trailer is not connected. The Prodigy display may show NC without a trailer connected.

I suspect you have a wiring problem most likely in the trailer.

I am not sure but the Prodigy may show NC if there is only one brake magnet active. This may explain why you can hear a noise at the trailer.

This is why I prefer the Prodigy P3. It provides a current reading and if there are not 4 magnets connected this can be detected by the current reading. My 4 wheel 5th wheel draws about 1 amp per volt applied.