Faulty ground or do I need converter

[marops]

I just installed "waterproof" trailer lights with a common 35 dollar kit(Peterson, I think). Lights work, but left blinker activates both rear lights and right blinker does same. I followed manufacturers diagram. Truck is a 2001 Dodge 2500 with factory trailer package, so I'm using the round to 4-pin flat adapter that came with truck. It has ABS brakes. Reason I say that is somebody in local Marine shop (where I purchased trailer parts & lights) said that late year trucks with ABS brakes have an issue with standard trailer lights...said I need a dodge-specific converter. Another guy at the local U-Haul said it's probably a grounding problem.<br /><br />I'll fiddle with the ground tonight and see if I can get the blinkers to work correctly. Does anybody here think a converter would be the solution?<br /><br />Any help much appreciated.<br /><br />Thanks,<br />-Jack

 

[Ralph 123]

Re: Faulty ground or do I need converter

I had exactly the same problem on my GMC. I found that the ground wire (white) on truck's round connector was broken under the bumper. I attched it back to the frame and it worked fine.

 

[marops]

Re: Faulty ground or do I need converter

Thanks Ralph,<br />I inspected underneath: looks fine. I took apart the round-to-flat adapter and wired the 3 light wires(running, LH blink, RH blink) directly to the indicated posts, by-passing the male-female flat connectors and physically grounded both sides; no difference.<br /><br />I dunno if this ABS brake/Converter thing is a red herring, but I'm gonna do some more research. This simple light replacement ain't so simple...<br /><br />Cheers,<br />-Jack

 

[Ralph 123]

Re: Faulty ground or do I need converter

When you say you grounded both sides do you mean that you connected the trailer light ground to the truck ground? I wouldn't rely on the trailer frame for the light ground. I'd run it back to the truck.<br /><br />My GMC has ABS so I would be surprised if the problem was related to that. I guess anything is possible...<br /><br />Good luck

 

[marops]

Re: Faulty ground or do I need converter

The trailer side wiring has a white ground wire and the truck side wiring has a white ground wire(as above, I'm using the included flat connector and sticking it's bare ends into the female round connector mounted on truck). I haven't drilled any holes in trailer to screw the trailer ground wire down, so I just hold that against the trailer with one hand and hold the truck ground wire against the truck frame with the other. I even criss-crossed the grounds and tried all other combinations but didn't get different response...<br /><br />New development: If I turn on the lights (parking or headlight) the blinkers work as they're supposed to (left blinker: left trailer light only, etc...). I dunno why it doesn't work when lights are off, but that may be a clue to the solution. At any rate, that's enough for me to move on and continue building the trailer; I need to get the boat in by Friday. Guess I'll just make sure to turn on lights when trailering until I find a fix.<br /><br />Thanks again!<br />-Jack

 

[Ralph 123]

Re: Faulty ground or do I need converter

Jack,<br /><br />Just holding the ground against the trailer probably won't do it - paint, oxidation, etc acts like an insulator. Try this: Take a length of wire and connect the white wire on the trailer light (or the ground stud) directly to the white wire on the truck and make sure the white wire on the truck is connected to the frame of the truck. That should do it.<br /><br />RS

 

[roscoe]

Re: Faulty ground or do I need converter

This is a ground problem. The current from the signal light is not getting grounded properly. So it is traveling on the path of least resistance. Which happens to be thru the frame to the other signal light, then back thru that wire to your vehicle.<br /><br />Drill the hole in the frame or connect the ground wire to an existing bolt, like the one that holds the safety chains on.<br /><br />Or even better, Run a ground wire from each light, back to the ground in the connector.<br /><br />Then make sure the wire on the truck side of the harness is also screwed down.

 

[Bondo]

Re: Faulty ground or do I need converter

Take a set of Booster Cables, Hook one ends to your truck frame.... Hook the other ends to your Trailer Frame.... Wiggle,+ Shake them to be Sure you've Got Bare Metal......<br />NOW You Have a Good Ground......

 

[marops]

Re: Faulty ground or do I need converter

Hmmph. Still a bit stumped. I ended up mounting the lights (had them laying on trailer while testing) and figured I'd just turn on truck lights while trailering.<br />Now I've got different results, LH or RH blinker when activated produces an intermittant left then right trailer blinker (right blinks on, then left, then right...). Now that's a new variation...oh yeah, this is when parking/main lights are on in truck. As before, when lights are off, I get both R&L trailer lights blinking simultaneously when activating either blinker.<br /><br />I ended up drilling a small hole in trailer to secure the ground wire with a screw. The rear lights are grounded by the mounting bolts.<br /><br />Today, I'll swing by local Marine shop and hook my truck up to thier trailers so to rule out foul play by my truck's wiring.<br /><br />I think it's grounding too since I get inconsistent results. I'll connect the ground directly to known ground on truck to see if that helps.<br /><br />Thanks for all the help, this is truly a great forum.<br />Happy 4th!<br />-Jack

 

[Ralph 123]

Re: Faulty ground or do I need converter

Now that you have tied the light ground to the trailer I think if you try Bondo's idea of using the jumper cables to ensure a good ground between the truck and the trailer they will work fine. If they do, you just have to make sure the connector ground on the truck side is tied to a nice bare metal spot on the truck.<br /><br />Also note that when you are grounding through the trailer frame unless the trailer is hooked up (hitch on truck ball), the two grounds are not connected and the lights will act funny as you described. The grounds must be tied together either through the frames physically connected or with a wire. <br /><br />If you have a multimeter you should be able to touch a bare metal spot on the trailer and a bare metal spot on the fame of the truck with the other and read almost 0 ohms resistance.

 

[marops]

Re: Faulty ground or do I need converter

Thanks,<br />I'll try Bondo's suggestions.<br />I'll also check resistance with a multimeter.<br /><br />Hoping to post success soon....<br /><br />-Jack

 

[marops]

Re: Faulty ground or do I need converter

Success!<br />Bondo's suggestion ruled out "other than grounding" problems. Thanks, Bondo! Now to give my wife back her jumper cables...<br /><br />Glad I didn't chase that ABS crap.<br /><br />The only real solution I can think of then is to direct-connect a decent guage wire from the truck frame to trailer frame (the truck-side ground wire, although intact, just doesn't seem to be enough, as is the little ground wire attached to the trailer that was included in light kit).<br /><br />So the statement of trailer-light problems being ground related at least 80% of the time is supported again...<br /><br />Thanks again everybody!<br />-Jack