Trailer Lights Problem

[jamesm]

Hey All!

Its been a while since I have posted but I am still working on my trailer. I seems to have a slight problem with my trailer tail light wiring. Everything works but when I have a turn signal (lets say the right side) on and the running lights on then the left side running light fades on and of just a bit. This happens on both sides depending on which side the blinker is on. I have a dedicated ground to each tail light with no grounding thru the trailer itself. It seems to me that the system is feeding back to itself some how. But I am not sure....so that why I am here asking.. .

I did check the truck wiring with a test light and it is working properly with no "hot" wires other than what is supposed be.

Anyone have any reason this might be happining and how to correct it?


Thanks...James

[angib]

It sounds like a problem with the ground conductor - the extra current from the flashing light is causing a voltage drop on the ground conductor that results in less voltage drop at the other lights.

Causes could be:
- ground wire too thin (the usual problem over here with cheap multi-core cable);
- bad joint in the ground conductor;
- bad ground connection on the tow vehicle;
- bad joint in the trailer plug/socket.

Running a temporary extra ground conductor from lights to socket - rig a lash-up using one wire of a household extension cable - is a way to test the trailer's ground conductor, though it doesn't tell you if it's a wire size or bad joint problem.

Andrew

[kartvines]

mine also did that, still working at correcting it, you said add a additional wire for the light socket, what do you mean.

I was thinking about adding a wire to one of the mounting bolts, but was unsure if one was positive and one was ground , does it matter? I thought if I added a extra wired to one of the posts to a good ground it would correct this problem.

[jamesm]

Thanks Bullshipper...I went ahead and checked the ground on the tv. but the problem still exists. I then ran an extra wire for the ground from the tv to the lights. Sure enough the problem went away. Thanks a bunch for the help.

[angib]

Glad to hear that worked out.

One of the mysteries to me is how all trailer cable in Britain has the same size conductor for the ground as for the other circuits - all the circuits return through the one ground wire, so how come it isn't three or four times the size of all the others?

But then I don't know how skilled ladies make the tassels rotate in opposite directions, so whadda I know?....

Andrew

[BrwBier]

But then I don't know how skilled ladies make the tassels rotate in opposite directions, so whadda I know?....

Andrew

I think that need some more study.

[BPFox]

Glad to hear that worked out.

One of the mysteries to me is how all trailer cable in Britain has the same size conductor for the ground as for the other circuits - all the circuits return through the one ground wire, so how come it isn't three or four times the size of all the others?

But then I don't know how skilled ladies make the tassels rotate in opposite directions, so whadda I know?....

Andrew

It's not just an England thing. Typically on four flat connectors all of the wires are of the same size. It's not a problem since tail lights are a pretty low draw situation and the negative wire is more than large enough to handle the load. Now when you go to a standard RV 7 pin connector, the negative conductor is larger. Typically the white wire on a 7 pin is 10 ga where the tail light wires are only 14 ga. If you are just sporting a pair of simple tail lights, the 4 pin connector is fine. If you plan on having the full complement of D.O.T. marker lights, I'd go with the 7 pin RV connector with the heavier negative conductor. You will be glad you did.

[Maddy]

Trailer light rigs are usually of one of three varieties. Rig "A" has the light fixtures permanently bolted to the metal frame of the trailer and the ground "wire" is actually the entire trailer frame joined to the tow vehicle via the metal trailer hitch.





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[Dale M.]

Glad to hear that worked out.

One of the mysteries to me is how all trailer cable in Britain has the same size conductor for the ground as for the other circuits - all the circuits return through the one ground wire, so how come it isn't three or four times the size of all the others?

Andrew

Pretty much same in US with premade/factory wiring harnesses.....

That is why I prefer to do my own thing and run at least a 12 gauge or 10 gauge wire from tow vehicle to trailer and "bond" ground cable to trailer chassis...... Got to love 6 and 7 way connectors - Neven like the limited abilities of molded flat 4 connectors so prevalent in US.

Dale

[angib]

You might like the new European standard - a 13-pin plug and socket:



This allows separate left and right lighting circuits and several power leads. It contains three ground conductors - one for lighting and two for power circuits.

Andrew