Fontaine Revolution rear axle dump question

Is there a second light plug socket on the trailer? If so then you can apply 12v to each pin to find the one that dumps air.
If not then with air on the emergency side and the key on in the tractor, unplug the light cord and see if it dumps, if so the blue (center pin) wire needs an interrupt switch. That is if your truck has the blue hot for ABS power.
I have seen a dump on the black or brown wire as well if you have separate tail and clearance light switches. If so shut off one or the other to dump.

 

That's a picture of a plug alright. Is that your main plug or an extra?

 

12 volt electric is easy. It takes power and ground (+ positive and - negative) to make anything work. And electricity always follows the path of least resistance, that gets complicated but can do some wild things.

Anyway to activate your dump valve you will need power and ground. The valve is probably grounded through the frame or wiring harness to the frame already. So you should just have to apply power to one of those pins to activate the dump valve. Is there a manual or anything with the trailer and a wiring diagram?

 

Be willing to bet it is the pin that has a hole punched in the sticker diagram. lol

 

Dang, good eye! Didn’t notice that

 

yes and the large top pin (labeled white) will be negative (ground).