Annoying electrical problem

[chris jitr]

Hello, I have a problem with wiring on my vehicle somewhere. My trailer running lights work normal. My right brake light and right blinker work as well. However, my left brake light and my left blinker do not work on the trailer when hooked up to MY vehicle. I checked the hitch wiring on my vehicle with a multimeter and everything works properly. So I figured it was the trailer wiring. So I hooked the trailer up to my buddies truck and all the trailer lights worked perfectly fine. So I double checked the plug from my vehicle (flat four) and they all showed they were working properly. The only thing different was the left blinker showed slightly lower voltage than the right. I don't think it's a ground because all the other lights work and they are all hooked to the same ground. Not only that but they work on other vehicles I don't even see how this problem is phisically possible, but it is. I'm going on a big trip, and I need my trailer to pass inspection. I'm stumped, and I consider my self more than average when it comes to electrical problems. This should be easy. I also heard it could be the factory flasher unit. I replaced it with a heavier duty one and still no go. PLEASE HELP ME!!!

[Steve_Cox]

My bet would be the ground wire connections on your tow vehicle and on the left trailer light need to be cleaned off and tightened. Since it worked with a different vehicle, it seems that it could be from 2 not so good grounds not just one problem. Volt meters often will indicate ok voltage when the wire terminations are not capable of handling the load.

[madjack]

...believe it or not, it probably is a ground problem...first check the light fixture and make sure it is tightly and properly grounded, 2nd, check the ground wire on the 4 flat plug(on trailer) and make sure it is properly grounded,,,3rd check the ground on the 4 flat plug on the vehicle side to ensure it is properly grounded as well...what type of trailer frame do you have...welded or bolted...bad grounds are the cause of most problems and they will cause funky things to happen.....
madjack

p.s. by the way, it would have been real nice if your first post to this board had been to introduce yourself and not to address a problem......MJ

[Miriam C.]

That would just drive me nuts. Do the lights work when you wriggle the connectors? It might be that you aren't getting a real great connection when you plug it in yours. Could be that metal connector inside or the wire is loose.

First thing I would do is get it inspected using someone elses Tow. Then I would get an extension for the 4 flat to see if it is the plug itself or a wire.

Replacing the female side is not that hard because you can wire another on. Color coded.

OH and

[chris jitr]

Well I hardwired it before and after the module in the trailer wiring and I determined that the problem was in the module. The module is there because it is a forign SUV and it has to distigush between the blinker and the brake light since they are separate. Thanks for all the help though!