crazy boat trailer lights

[DeanWh]

I am trying here first just in an attempt to see if anyone else has had this problem before.
My boat trailer lights work perfectly fine during the day, but as soon as I turn my headlights on, they go all crazy.
For one, only the right tail light comes on, but also:
When indicating right, the right tail light flashes, with no indicator at all, when I indicate left, just the right tail stays on, still no indicator.
And then when I'm driving, if I am indicating left and apply the brakes, the indicator speeds up to double the speed.
Anyone ever had this before?
Cheers

[finga]

Check the earth wire from the car to each of the lights (including number plate light if you have one.
That'll be the white one if the trailers up to standard.
A prime spot to check is also the rivet that seems to join all the earths in the lights together. Corrosion occurs in the joint.
Sounds like there's a back feed through the other lights to get an earth on the trailer lights.

[eugah]

Is this happening when the trailer is connected to the car (I mean correctly hitched up) not just hooking up the trailer plug to car. I have seen this problem on a caravan when testing lights by just having the electrical side hooked up there was not a good enough earth. Once the caravan was hitch to the towbar there was a better earth & all lights worked as per normal.

Hope this helps

Adrian

[finga]

They should not be relying on the earth through the coupling.
There should be a white wire in the loom.
If they are relying on the earth through the connection of the coupling then I would be getting it fixed.

[Roughasguts]

Yeah this happens all the time with a bad earth.

Just to confirm make a jumper lead and conect it to the chasis of your car and conect the other end to the trailer.

If it works okay theres your problem, clean the tow ball coupling and then clean or renew all earth wires, on the lights. In fact you may as well just re new all the wiring cause it don't last forever the wires start to wick then turn to dust, it happens quicker in the salt enviroment.

[PADDLES]

like finga has said, the earth return should not be through the towball but through the earth conductor in the cable, it's possibly broken or disconnected somewhere and there's a backfeed through the other bulb circuits.

[tunaticer]

Definitely a bad earth or as a professionally wired towbar i had fitted on a work ute they had used the auxilliary power circuit on the car as the earth and as soon as something was switched on things went completely stupid.

Jack.

[oldboot]

Yep as finga said in the first place, classic bad earth symptoms.

when operating with no tail lights the flashers and brake lights operate by earthing via the tail light filaments.

when voltage is applied to the tail light circuit that path is no longer available.... so weird things happen......

It's one of the sillyest faults you will find in auto electrics.;D ;D

Don't think about it too much the cause is obvious, just remake your earths at least.

happens with cars too.... old holdens were bad for it.

brake lights come on tail lights go out:-/
indicators & tail lights flash:-/

anything similar to this will be the same thing.

cheers