Trailer electrics

[Rainman]

The lights (brakes and indicators) on my trailer don't seem to be working correctly and I'm not sure if its the connectionon the vehicle or the actual trailer. Is there any easy way to check the trailer lights without having to hook it up to the car? I have a seven-point plug. Is it just easier to take it to the auto-electircian?

Cheers

GD

[Roughasguts]

If it worked before with no problem, and all globes are fine.
You will find you have a bad earth, for example if you turn your indicator on the brake one brake light will flash and the indicator glow.

So clean up the tow ball coupling, try a jumper wire from car to trailer (extra earth lead). Trailer needs to be on the car for a good earth.

If your chasing wires un screw both car plug and trailer plug and compare the colours, if there all the same, there should be no problem unless some one did a bodgey colour code.

If all fails try a test light at all the globes test seperate indicators, tail. and stop lights.

[Chimo]

Agree with RAG re the earthing but depending how they wired it, if they used the trailer body as the return the connections between the individual light bodies thru the nut and bolt to the bracket or mudguard is worth checking.

I just had the same issue on a trailer and repairing these connections, especially where things get wet is what fixed it.

It is alo the easiest to check if not a bit fiddly.

Try it anyway?

Cheers
Chimo

[Roughasguts]

Must, admit I run a extra earth wire from each tail light, just a short one to just outside the light, and screw that to the chasis, with S-S washer and bolt. Makes a quick easy clean rather than break the seals on my submeribles, and clean it up that way.

[finga64]

Where are you Rainman??
If your on the southside you can come around and get them fixed but that offer is for today only.
Gone fishin' tomorrrow for awhile
Sometimes it's quicker and easier to rewire. That way you know it's right.
In a 7 pin there should be an 'earth' wire and it's white. And that white wire should run to all the lights and, if fitted, electric brakes.
Red is the brake light, brown is the clearance lights and yellow and green are the indicators so if you have a multi-meter just make certain all the wires have a good circuit (less then 1 Ohm or the buzzer goes buzz if it has a continuity checker) from the plug to the right place in light.
the best place to check is actually on the contact where the bulb sits.

[BaysideMarine]

Rainman,

If you are looking at the back of the trailer plug, ie: where the wires connect to the plug the sequence is thus:

12 o'clock (for 7 pin wiring or 1 o'clock for 5 pin wiring) = L indicator (yellow)

6 o'clock (for 7 pin wiring or 7 o'clock for 5 pin wiring) = R indicator (green)

11 o'clock = brake lights (red)

centre = tail lights (brown)

5 o'clock = earth (white)

It is best to cross link your 7 pin plug on the vehicle so that a link wire runs between 12 o'clock and 1 o'clock and another link wire between 6 o'clock and 7 o'clock. That way if your towing a boat with a 5 or 7 pin plug it won't matter as your indicators will still work.

HOWEVER, if you tow a trailer with electric brakes then cross linking your plug will cause you problems.

Whenever I repair a customers trailer lights I replace the cable, plug and lights as it is a lot faster that way and also everything is new and is guaranteed to be good.

Cheers

[finga64]

Good thought about the locations BM

Better still as most plugs in QLD are 7 pin flat and who knows where Rainman is.
So if the o'clocks don't work real good because you have the flats or if you have a digital watch you can look hard on/or near the terminals you'll see the terminal numbers.
Terminal 1....left indicator.....yellow
Terminal 2....axilary or reversing signal.....black
Terminal 3....earth......white
Terminal 4...right indicator....green
Terminal 5...electric brakes...blue
Terminal 6...stop lights....red
Terminal 7...tail/clearance....brown
Not a good idea to do the link wire thingo. Gets a bit confusing and it's better to an adaptor to go from 7 pin flat to 7 pin round or to 6 pin.

Just thought. Are you talking about the huge 7 pin round plugs BM??
They don't use them up here in QLD and a 5 pin round will not go in a 7 pin round socket.

[BaysideMarine]

Yes!!!

Must admit I was thinking of 7 pin large round at the time of posting.

As you mentioned flat 7's have the connections marked in the casing so thats easy enough.

Pin linking in a large, round 7 makes perfect sense and will cater for any trailer other than an electrically braked trailer.

Cheers

[Reef_fisher]

After constant problems with lights on trailer I stripped everything off, got new plug through to lights and wired them to 2 brackets that attach to the transom hand holds. Yes I have to removed lights prior to launch but have never had a light problem since and I used cheap generic trailer lights, cheap to replace if damaged. Wiring runs through boat when hooked up and takes 30 seconds to disconnect and put in ute.

I also lifted ute plug up under tray because ute plug was getting rubbish including water thrown up onto it causing it to corrode (terminals)

Cost about $45 to renew everything.