back-upl ights on trailers? 5-prong plug

Wood Zeppelin

Hey all,

I have new trailer for a 22' Cdory, with hydraulic surge brakes. It has a 5-prong plug, my tow vehicle has a 4-prong plug.

Am I correct in assuming the 5th prong is for back-up lights?

If so, do 22' trailers usually have back-up lights? (Previously I have only has a 16' trailer, 4-prong plug, no back-up lights)..

thanks!

ssobol · Posted: Thu Oct 06, 2022 4:45 pm Post subject:

Most boat trailers do not have backup lights. The vehicle backup light circuit is tapped to control the trailer backup solenoid. When the solenoid is on, the brakes on the trailer will not be applied when backing up (this would normally compress the surge cylinder and apply the trailer brakes). On some trailers you can manually disable the brakes for backing. Since that automatically resets when moving forward, moving the trailer back and forth (say getting into a tight parking spot) can be a PITA because you have to keep setting the bypass. Having an electrically controlled solenoid is more convenient.

Wood Zeppelin · Posted: Thu Oct 06, 2022 8:05 pm Post subject:

Ah, yes, of course!

Thanks for informing me..!

thataway · Posted: Thu Oct 06, 2022 8:51 pm Post subject:

There are several ways of bypassing the surge brakes when backing. One is a hole thru the frame so the surge brakes would not apply. Also "Chain Vise Grips" can be locked around the frame. This way, you can back and fill all you want, with the brakes off.