Cosmos Posted August 1, 2011 Report Share Posted August 1, 2011 Hi guys, I had to put a new lights for my trailer and i did something wrong. I used to have wiring done for my car once i had hitch installed by Hitch company and i never touched anything. My driver's trailer light wasn't working since i bought my boat and i decided to open it for checking, i found rust everywhere, i cut i cable and found that copper wire is black(which i guess is bad thing). Took my passengers lights and connected it to the driver's - i think this way i can see if wire is still good to use, because it was not working i decided to put all new. Went to CT and got a brand new set of lights, put them and connected. Put the light on and NOTHING, turns and stop lights are working fine, cars lights are ok as well, but on the trailer once the light are on trailer lights are still off. As i said i didn't touch anything in the car, there is some kind of red small box installed between car lights and trailer harness in the car as well. I am wondering if somebody can give me a good advise what to do. Any help will be greatly apprecited. Link to comment Share on other sites More sharing options...
DRIFTER_016 Posted August 1, 2011 Report Share Posted August 1, 2011 Check your ground wires, especially the one between your tow vehicle and trailer. Link to comment Share on other sites More sharing options...
Cosmos Posted August 1, 2011 Author Report Share Posted August 1, 2011 Check your ground wires, especially the one between your tow vehicle and trailer. Are you talking about white cable? Using a screw i attached it to the trailer frame. Link to comment Share on other sites More sharing options...
Woodsman Posted August 1, 2011 Report Share Posted August 1, 2011 If you know someone with a trailer that has good working lights & the same type of plug as yours, hook up your vehicle plug to his/her trailer just to confirm the problem is in your trailer & not the tow vehicle. I just had a friend show up at my place with his trailer blaming his trailer light problems on his trailer only to find out when I hooked up my magnet mount lights that they acted exactly the same. Problem is in the tow vehicle. Best to identify where the problem is before working on the fix. Link to comment Share on other sites More sharing options...
scugpg Posted August 1, 2011 Report Share Posted August 1, 2011 Do you have a volt meter to see if the trailer plug at the hitch is getting juice and ast the back of the trailer? Link to comment Share on other sites More sharing options...
Cosmos Posted August 1, 2011 Author Report Share Posted August 1, 2011 Just a small update - i was checking lights when car wasn't on started. I started the car and none of the trailer lights are working now, car lights are OK - all of them. Once car is on none of signals are working on the trailer. But once the engine is off, turn signals and stop signals are OK. I guess i have done something to car wiring once i was switching the lights. Link to comment Share on other sites More sharing options...
scugpg Posted August 2, 2011 Report Share Posted August 2, 2011 Hmm maybe the parking lamps are causing the issue? Duf you have the lights on when the car was off and you were testing the signal and brakes? Link to comment Share on other sites More sharing options...
Cosmos Posted August 2, 2011 Author Report Share Posted August 2, 2011 (edited) Hmm maybe the parking lamps are causing the issue? Duf you have the lights on when the car was off and you were testing the signal and brakes? When car is off and the light are off, signals and brakes are working. Once lights are on doen't matter car engine is running or not - they aren't working any more. I guess i screwed up with converter, i will try to connect wires directly tomorrow. Will keep you posted. Edited August 2, 2011 by Cosmos Link to comment Share on other sites More sharing options...
scugpg Posted August 2, 2011 Report Share Posted August 2, 2011 Sounds like a short with the running lights on the trailer. Double check all the wiring you can get to. If you disconnect the drivers trailer light can you get running lights on the passenger side? Link to comment Share on other sites More sharing options...
Cosmos Posted August 2, 2011 Author Report Share Posted August 2, 2011 Sounds like a short with the running lights on the trailer. Double check all the wiring you can get to. If you disconnect the drivers trailer light can you get running lights on the passenger side? Same thing - not working, tried already. I think i did something to converter when i was switching light in the first place. I already checked all wiring. I guess will have to buy a new converter and try with it. Link to comment Share on other sites More sharing options...
Bernie Posted August 2, 2011 Report Share Posted August 2, 2011 Hmmm. I'd still bet on a bad ground. When the lights are off the signal/brake is getting ground through the running lights. As soon as the lights are on it becomes powered positive and no ground is available. The best way to test cicuits in a trailer connection is with a 12 volt incandescent test light. Using a multimeter you need to check resistance, not voltage. Voltage can often show good but a poor connection will not flow enough to light a bulb. Said it before and many others here have as well......CHECK THE GROUNDS!!!! Link to comment Share on other sites More sharing options...
irishfield Posted August 2, 2011 Report Share Posted August 2, 2011 Almost seems like a wiring post needs a "sticky" to keep it grounded eh Bernie ! Link to comment Share on other sites More sharing options...
Cosmos Posted August 2, 2011 Author Report Share Posted August 2, 2011 I will check the ground tomorrow morning again. Thank you for your advise. Link to comment Share on other sites More sharing options...
Bernie Posted August 2, 2011 Report Share Posted August 2, 2011 I'd say it may be a good idea Wayne. Ha! Yellow is left turn and left brake light. Green is right turn and brake light. Brown is running lights. AND....white is ground! You need to verify the ground is good at the plug from the vehicle too. Don't count on the ground working through the hitch. Most of the time it doesn't. Link to comment Share on other sites More sharing options...
blue pickeral Posted August 2, 2011 Report Share Posted August 2, 2011 If you have a 12 volt car/motorcyle etc. battery around and a couple of wiring probes/clips, work from the trailer hitch area without it plugged into the vehicle. Attach one of your probes from the negative pole of the battery to the white wire or its plug - this is your ground. In turn, attach a probe from the positive pole of the battery to each of the other coloured wires in turn - brown (tail lights),yellow(left), green(right)-and see if they light up. Link to comment Share on other sites More sharing options...
Cosmos Posted August 2, 2011 Author Report Share Posted August 2, 2011 Picked up a small tester from CT to check the connection. It's showing the issue with car wiring, will change converter today. Link to comment Share on other sites More sharing options...
davey buoy Posted August 2, 2011 Report Share Posted August 2, 2011 Picked up a small tester from CT to check the connection. It's showing the issue with car wiring, will change converter today. Why does he need a converter? maybe just lucky but on my last 6 vehicles,never needed them. Link to comment Share on other sites More sharing options...
DRIFTER_016 Posted August 2, 2011 Report Share Posted August 2, 2011 Why does he need a converter? maybe just lucky but on my last 6 vehicles,never needed them. Separate brake and turn signals on tow vehicle to combined turn/brake signals on trailer. Link to comment Share on other sites More sharing options...
Bernie Posted August 2, 2011 Report Share Posted August 2, 2011 (edited) Hmmmm again. I suppose there is a possible bad convertor but still think it is something else. Running lights go direct through the converter, it doesn't change it. And the signals and brake lights were working when running lights were off. This tells me the converter was doing it's job. Still think the ground out of the vehicle is not working. If the device you bought at CT is the one with the 3 little diode lights it will often fool you. Diode lights draw very little power. The incandescent ones on the trailer draw quite a lot more amperage. Those diodes often light when there is still an issue. Edited August 2, 2011 by Bernie Link to comment Share on other sites More sharing options...
Cosmos Posted August 2, 2011 Author Report Share Posted August 2, 2011 Bernie, I think you are right. This tester was not working on the old converter at all. With new converter it's showing all good. Once trailer is connected passenger side is working fine, but drivers isn't, I guess you are right - it's something wrong with wiring on the car side. Will take a car to mechanic and will have it install by pro. Link to comment Share on other sites More sharing options...
irishfield Posted August 3, 2011 Report Share Posted August 3, 2011 Bernie is telling you it's a trailer issue and not a vehicle issue. Take a booster cable and clip it bumper to trailer. Work now?? If not.. see how they grounded each light unit. Many just put a pig tail under the attach bolts for the lamp housing and you'll find this rusted. Link to comment Share on other sites More sharing options...
Cosmos Posted August 3, 2011 Author Report Share Posted August 3, 2011 Irishfield, I was using magnetic lights for testing, same thing - passenger side is ok, drivers isn't working. Link to comment Share on other sites More sharing options...
blue pickeral Posted August 3, 2011 Report Share Posted August 3, 2011 Why does he need a converter? maybe just lucky but on my last 6 vehicles,never needed them. To save a few cents per vehicle, the manufacturers are running several different items through the same wiring circuit - in the case of my truck, the vehicle tail light circuit (which is separate from brake lights and turn signals) has parts of the ABS brake system, dash board indicators and a couple of other things. Consequently, if a short exists in the system somewhere, back flow of current can occur with bad results. Originally I bought an after market converter for the truck, but this failed after a year. Bought the OEM from the dealer ($arm and $leg) but creates separate wiring circuit for trailer towing so less problems overall. Link to comment Share on other sites More sharing options...
Cosmos Posted August 3, 2011 Author Report Share Posted August 3, 2011 Guys, I didn't ask if i need to check any fuses? Link to comment Share on other sites More sharing options...
Sinker Posted August 3, 2011 Report Share Posted August 3, 2011 If you had no power at all out of the vehicle, I'd say check a fuse, but since most of your lights are working, I think its a bad ground, or a bad connection on that circuit. Are you hooking the trailer to your vehicle when your testing the lights? Sometimes my running lights will do the same thing, then come on once I drive 50ft down the road. There is a bad ground in there somwhere that grounds out thru the hitch once I move a little. If I don't have the trailer hooked to the vehicle, the running lights won't work for me. I ran a separate ground right from the plug to each rear light to cure this problem. S. Link to comment Share on other sites More sharing options...
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