trailer lights plug in

[bucketmouth64]

All my trailer lights work except for my left blinker. New LED lights put in last year. I have one of those round plug ins. I think that is the problem. I have to jiggle it around to get the lights to work. I think the contacts may not be connecting good. Wondering if I should just cut it off and switch to regular flat plug in or if I should buy a new round plug in set. Any opinions? What plug in do you use?

[Hookmaster]

I had some trouble with my round plug in this spring. Just the running lights on the trailer wouldn't light. The right and left turn signals did. I checked out the round to flat adaptor for any breaks in the connection through it and it was OK. Then I looked at the round plug in on the truck. No corrosion on the trailer side. I unhooked the harness from the back side and noticed corrosion on the ground. I cleaned it off but it hadn't interfered with the trailer turn signals. So I went to the fuse box under the hood and the fuse that controls just the trailer running lights had blown. I don't know why. I replace it and it has worked fine since. My truck is a 2004 Silverado. It has fuses that control just the right trailer turn signal, just the left trailer turn signal and just the trailer running lights. It has more fuses than any vehicle I've had in three different fuse panels/boxes. I would check your manual and see if you have individual fuses for the trailer turn signals.

[MuskieJunkie]

I have the same problem with my rig. I know the lights on the trailer work, and my truck is only 2 years old so I am pretty sure they work. My round adapter is about 5 years old so I guess it's due to be replaced. How many years do you guys usually get out of those adapters?

[Surface Tension]

bucketmouth, it sounds like your plug is dirty or the contacts just wore. I'd clean the contacts and give it a try.

If that doesn't work you can can tweak/bend the male ends a hair. In the end you might end up having to replace the plug.

[Shack]

What make and model is your truck or car? If it is a late model, fuse panel under hood would have fuses for trailer lighting. The easiest way to check the whole fuse panel in seconds is with a test lamp. Hook test lamp to ground (clip end) and turn ign. on and turn signal on. Use probe and check each back side of blade (minny or reg.) fuse. The back side of a blade fuse (the side with rating number on it) has two little opening's to probe check to see if good. One side will allways light up. If one side does not light up, this means fuse is blown. If you prefect this (it is easy).

See on top of blade fuse. There are two little slits. If power is going to fuse and fuse is good, when you stab test probe on each side, test light will light up. If fuse is bad, only one side will light up. You can test a hundred fuses in seconds with this method. Keep going untill you find a blown fuse, if not the connector or wiring concern would be my next place to check. Possibley a ground issue with that light. I never open a owners manual for fuse any more. this method is cool and quick! Good luck!

[bucketmouth64]

How do you clean the male ends? I tried to get in there with sandpaper and not having much luck because the space is small. What about the female end cleaning the inside? Is that worth looking into? Any kind of chemical work?

Shack, I have a '98 Explorer. I don't believe a fuse is the problem, but I will take a peek at it.

[Surface Tension]

It wouldn't be the fuse if you can wiggle the plug and it works but the info is still good.

CRC Electrical Cleaner.

[efgh]

The round plugs, male, on my plug have a slit in the very end of them, stick a small knife blade in the end and open them up a little, plug and unplug a few times to make better contact.

[Surface Tension]

Very good suggestion efgh.

[Shack]

Sorry, my bad! I did not read close enough. I must of been putting first two posts together.

[HaywardBound]

Quote:

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How do you clean the male ends? I tried to get in there with sandpaper and not having much luck because the space is small. What about the female end cleaning the inside? Is that worth looking into? Any kind of chemical work?

Shack, I have a '98 Explorer. I don't believe a fuse is the problem, but I will take a peek at it.

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I couldn't find a chemical, but I used a Dremel tool on my plugs. A little wire brush for the male, and another small tool to get inside the female parts. Worked great!

Quote:

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CRC Electrical Cleaner

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ST, where can I find this stuff?

[Shack]

I use any battery post cleaner. You can also use Coke cola or I have heard baking soda.

[stmichael]

Diet coke works just as good as regular coke, just not as sticky.

[bucketmouth64]

Just think people drink this stuff . Kinda makes you think how our body can take it. Anyway, good ideas from you all. I will have to try these out this weekend.

[Surface Tension]

You can find the CRC brand at most high end auto parts stores, but any electrical cleaner should work.

The coke works because of its acid. Next time your at the dentist look for the chart that shows which soft drinks are the worse for your teeth and pick that one.

[bucketmouth64]

Ok, this is really getting frustrating. I cleaned what I could and I bought a circuit tester. I found two wires that have no power going thru for the left side...blinker/brake lights. There is no power where they are connected to the vehicle wires. Is it possible that I have these two wires crossed? Would that cause no power in the wires? I tried to probe the wires by the trailer box, but I can't get a ground to work so I can use the probe. Any ideas how to get the probe to function? Left blinker and left brake light is all that doesn't work. Right side works and both lights.

[Hookmaster]

Put the round plug in into the round socket on the vehicle. Put your lights on. Take the negative of the circuit tester and put on the exposed connection on the four pin side. Test each hole until the tester lights. Remember which hole it is. Now turn on the right signal light and try the other two holes. One should light intermittently. The other hole that hasn't lit up is the left signal light. Now turn the left signal light and try the remaining hole. If it doesn't light it might be the round to four pin connector, the wiring to the round connector or a fuse. In my case it was a fuse. I could check the round to four pin connector with a volt meter so I knew it was good. I had power to the round connector since I unhooked the wire harness that went into it. The last thing I checked was the fuse. Do you know anyone who has a round connector to try?

[chris63]

If you guys are talking the four plug connectors that have the removable inside plastic plug (small screw to remove from aluminum housing)there are four small set screws that come loose from vibration,ect.When installing these make sure you soldier the ends of the wire before you clamp them with the set screws.Also one more note,make SURE all your ground connections(trailer and tow vehicle)are clean and rust/dirt free as ground problems,(current bleeds/drops non continuity )are often the result of "bad" grounds.This can lead to popped fuses or inoperative circuits all together.Hope this helps some.c63