Tap brakes -- parking / running lights come on?!?

[APersondek]

Howdy,



I just got done towing a two-place enclosed snowmobile trailer on a thousand mile round trip to Canada (Wawa) and back. The trip was great. Weather was not super cold; mostly teens and twenty's. When I got home and dropped trailer and pulled the truck into the garage, I noticed the parking lights and roof marker lights were on even though the switch was in the off position. I took my foot off the brake pedal and they went out.



The brake lights still work. I have checked several fuses and tried switching a couple of relays with the same part # to make sure it wasn't a bad relay. I cleaned both the 7 pin connector (the one used to tow trailer) and the flat 4 connector that was not used as well.



None of the above has fixed the problem. Please see sig below for specs of my truck. Has this ever happened to anyone? Please advise, thanks in advance.



Edit / note: I have checked and no codes have been set as of yet. According to the odometer anyway.

 

[dmurdock]

Did you wire the trailer connector or the brake controller?... sounds like the running light and brake light circuit are connected and that would be my guess. If you have the factory trailer connectors, try unhooking the brake controller and see if that fixes it. . if so, there's the problem.

 

[APersondek]

Unfortunately it is a small two-place trailer. It does not have any brakes. I don’t even have a brake controller hooked up yet.



The fact that I don’t think this started happening until after I unhooked the trailer is what I find pretty weird about all this.



note: the trailer was made in factory. it is a Triton XT series. I have towed it will other trucks before and not had problem thus. far. I towed it about 400 miles a few back with no problems.

 

[Midnight]

I have seen a couple times in the past where as one of the rear bulbs are at fault. The two elements touch together and when the brakes are on so are the running lights.

 

[APersondek]

well it looks like i will take it into the dealer tomorrow morning to see what they can find. I hope my first service experience is a good one...

 

[Casey Balvert]

As Midnight indicated, I have seen this happen when filaments short out to each other in a bulb. I would check that first. Might save a trip to the dealer.



Casey