Left trailer signal lights inop. on the truck side.

[GSchneuer]

My left trailer turn signals do not work on the truck side to the 7 pin rear plug.

No error codes shown. All fuses are good. The flashers, lights & right trailer turn signals are ok.

I cannot get my service manual CD to run on my computer, so I need HELP.

The wire color from the rear plug to the in cab plug is Yellow/wpink stripe all the way (I think).

I don't have enough wire to do a rear to front continuity check.

The front Yellow w/pink wire from the front plug looks like it goes up into the Column?, but I am not sure.



Has anyone else had this problem?, all Help would be very much appreciated.



Thanks, Gary

 

[mweiman]

Unfortunately the turn signal flasher/relay is internal to your power distribution module under the hood and is probably burned out. The 15 amp fuses are too big and the circuit will burn out before the fuse blows. If you search no trailer turn signals in the 3rd gen section you will learn all you need to know. Switching to 10 or even 5 amp fuses will prevent future problems. I believe it was only the 03 and 04 models with this problem.

Matt

 

[GaryOwen]

I had the same problem with my 03 when I was on the road. I made a test light from a spare bulb and some wire. Then stripped a small section up front and ran to ground. In my case it was working up front, so I replaced the last four or five feet of wire before the plug (all the wire I had with me) and it fixed the problem. I later checked the bad wire and found the wire was broken internally, but the insulation was fine. That was a new one for me. I don't recall the color of wire though.

 

[JFought]

i just found a melted connector at the bumper that plugs into the back of the dodge 7 way trailer plug. defiantly some of my intermittent problems.

 

[DE Jeeper]

same problem on my truck. i went to pep boys and bought the trailer lights tap in kit. it is a universal kit for tail lights that have a seperate brake light ($30). i just cut the factory trailer tail light wire and spliced the box in. if you run a lot of lights get the self powered version ($50). heck of a lot cheaper then 250 for the pcm. there are some picks on the web of people soldering on new relays or adding wire to the board for external relays. just seamed like to much work and risk. my cheap fix has worked for 3 years now only issue is the hazards on the trailer only light up the other side, but i put the turnsignal on for the repaired side and it looks like 4 ways. the soldered on board relays are just a bad design



aaron

 

[Kry226]

I went through this too.



Here's the fix: Upgraded Heavy Duty Modulite Circuit Protected Vehicle Wiring Harness with Install Kit Tow Ready Wiring 119190KIT

 

[JZellers]

I had the same issue this past summer with mine. It was the relay on the PDC for the left turn that went bad. If you go under the hood with the turn signal on you'll probably be able to hear the difference between the right and left turns. Something actually breaks inside the relay and it sounds like it buzzes and clicks instead of just clicking.



There are direct replacement relays (better quality) that you can get and solder to the board. This job isn't for everyone but if you're comfortable with it, it only takes a couple hours. I added the new relays and changed the fuses to 10A from 15 because as mweiman indicated, 15A won't blow before damaging the board and/or relays.



I also added a Modulite Ultra module which was easy in my case because I already had a good power feed to the rear of the truck and this would prevent any further issues. You could do just this alone and work around the PDC problem. These devices only take milliamps of power off the truck turn and parking lamp circuits.

 

[cowboysgottacummins]

Had the same issue on my 03 1500, I just tapped into the trucks turn signal with a t-tap directly into to the 7pin plug, no issues.

Also had the issue on my 06 3500 (was present when I bought it) this time I paid the dealer $70 to reflash the TIPCM. Which did the trick no problems since. You can only reset so many times and if the circuit is fried it wont reset, but it costs something like $800-$1000 to replace teh TIPCM so if it wont reset just tap the truck signal. Of course be sure to cut the signal wire going into the harness of the 7pin plug to prevent back feed and diagnose any potential shorts in your trailer first so you don't fry the truck lights.

 

[JKFaellaci]

I found your post on the thread for trailer turn signal failures. I have an 03 with the same issue that just occured. My turn fuse is good, the wire is good, I don't get a flashing signal on my trailer connector pin. I tow a fifth wheel RV trailer and utility trailer. I like the sounds of your solution compared to the others and would like to do it the way you did. If you don't mind, could you tell me how to find the board with the relays? Also, could you explain what the Modulite Ultra module is and where I can get one? A big thanks for your help!

 

[JZellers]

I bought the Modulite Ultra here: http://www.etrailer.com/Custom-Fit-Vehicle-Wiring,Wiring/Tow-Ready/119192.html These are designed to tap into vehicle circuits to power trailers without overloading the circuits because it has a separate power source and only uses milliamps of input power from the turn signals/running lamp curcuits on the vehicle. To hook it up on mine, I bought a t-tap harness so I'd have the proper male/female connectors to use the truck tow harness as inputs to the Modulite, then connected the outputs to the truck's 7-pole connector. That way I could always quickly disconnect the module and go back to the factory setup for any reason.



The relays are in the fuse box, under the fuses. A guy on DTR did a fantastic job documenting this procedure with pictures: http://www.dieseltruckresource.com/dev/power-distribution-center-pdc-repair-part-2-t222373.html That's what I used and it worked perfectly.

 

[cowboysgottacummins]

I found your post on the thread for trailer turn signal failures. I have an 03 with the same issue that just occured. My turn fuse is good, the wire is good, I don't get a flashing signal on my trailer connector pin. I tow a fifth wheel RV trailer and utility trailer. I like the sounds of your solution compared to the others and would like to do it the way you did. If you don't mind, could you tell me how to find the board with the relays? Also, could you explain what the Modulite Ultra module is and where I can get one? A big thanks for your help!

On my 03 the relay was labeled on the top of the fuse box. What I did was simply tap directly into the truck's turnsignal circuit. I never did by the modulite module. I just used a tclamp (cold use a scotch clip) connecter and found the truck's turnsignal wire responsible for the Left turn signal. Then I found it on the 7 pin connector, I follwed it back a foot or so from the 7 pin connector and cut the dead wire to prevent feed back on the affected circuit. Then I used a spare piece of wire and tapped the truck signal wire to the wire remaining at the 7 pin connector. taped it up tight and it worked great.



But on my 06 had the same problem on the right side and just paid the dealer to reflash it and it still works great today.