Mikey G

Everything comes on fine, but the tail lights and running lights stay on on the trailer after I shut the truck lights off, but not all the time. Sometimes they go off with the shitch somestimes they don't. I checked the voltage at the plug, with the lights off, sometimes theres zero, sometimes theres about nine and a half volts, sometimes theres about a half a volt. ???????????????????
Has anyone ever had this problem?

Mikey G

And It's not a short in the back of the truck, I've already checked all that out.

Kevin B

I assume you have an electronic brake controller. Is it possible there is a bare wire or a cross connect comming from that going to the wiring harness of the trailer?

donhov

Also a bad ground will wreck havick and make any diagnostics very difficult. Try making a temporary ground between truck & trailer, a bare wire clamped to each vehicle and see if problems go away, if so look for a bad ground on the trailer or truck.

Just another thought....Don

whoahoss

check the constant hot on your plug. sounds like a wire is touching to it or one is crossed

may want to check eack one with a aux. power source or ohm meter

whoahoss

if all else fails check the ground

that can do some crazy things that will drive you crazy.

whoahoss

the constant hot is the one in the center of the plug if I remeber right

tool

Aren't most wired with brake power on the centre pin?

RustyJC

See HERE for the Pollock 7-pin trailer connector wiring convention.

Rusty

whoahoss

sorry for the wrong info

tool

Whoahoss, by that diagram you are right.....

It's strange, I ust picked up a 7 way plug from a truck and oilfield supply place on saturday and it said right on it, centre pin brakes........


Strange.

RustyJC

On the Pollock connector, trailer brakes are at the 7:00 position (pin #2) on the truck plug. The center pin (pin #7) is used for back-up lights.

Are you certain that you're not confusing the 7-pin flat blade Pollock connector that comes on our trucks with a 7-pin round pin connector used on semis and larger commercial trailers? That's a whole different beast!!

Rusty

XLR8R

Mikey G - have you altered the factory wiring for the trailer at all?

tool

On the Pollock connector, trailer brakes are at the 7:00 position (pin #2) on the truck plug. The center pin (pin #7) is used for back-up lights.

Are you certain that you're not confusing the 7-pin flat blade Pollock connector that comes on our trucks with a 7-pin round pin connector used on semis and larger commercial trailers? That's a whole different beast!!

Rusty

Yep I'm definitely sure as I have round pin Semi type plugs on other trailers, since my stock trailer etc has the fllat pins like a RV I figure I'll wire this one the same.
This plug was labelled centre pin brakes.......

weird.

Very annoying too.

I'm gonna have to check out the way my stock trailer is wired.