2004 Dodge 2500 4x4 Hemi
I went to go fishing this past weekend and when I hooked the lights up my right turn signal would not work. It's not the trailer. The left works fine, running lights work fine. I have checked all fuses twice. The wireing harness is factory and hooks in up under the hood not back by the brake lights. Anyone have any ideas what to check next?

First of all


When you get the chance, go to the new-member's section and tell us about you and your truck.

I'm not sure what you mean about a factory trailer harness under the hood. I never heard of that, but checked the '04 service manual just to be sure. I still didn't find anything. Is it a regular 4-way trailer connector? Or, did you mean under the bed?

If it's the one under the bed, there may be some corrosion on the connector. This happens a lot since it's exposed to the elements. You could try cleaning the connector with a small wire brush.

The second thing I would check is the trailer wiring and bulbs. It's possible that there may be an open/shorted wire somewhere along the way.

Thanks for the response, let me try and clear it up a little.
Yes it's a four wire flat that comes out under the rear bumper. It appears to be a factory wiring harness, it also houses the wires to the license plate lights and rear tail lights. But the trailer light wire I have traced back up to the front of the vehicle meaning they don't just come off the truck tail lights. I get left turn signal and running lights at the 4 way flat plug but no right turn signal. The wiring harness runs up under the bed to another connector located under the drivers side front finder. From there I'm assuming it goes to the fuse box but not certain. I have checked there and no juice on the leg for the right turn signal. I have checked all fuses (all of them not just the turn signals) twice and they are all good. All the lights work on the truck itself so I don't believe it's the switch or anything like that. So bottom line I'm at a loss and feel like it's a simple thing I'm over looking. I hate to take it in and spend $80.00 for a simple fuse/relay/bulb.

Once again thanks for the advice and yes I'll sign in at the new members section and say hello to everyone tonight. Thanks again Lee

Okay, I understand what you're talking about now. If your truck turn signals work, then there shouldn't be a fuse/relay issue. It sounds like the wire in the trailer harness in the truck is open or not connecting somewhere along the way.

I noticed you said you checked most of the wiring. I'll see if I can get the wire colors that come from the fuse block all the way to the back so it makes it easier for you to find.

This message has been edited. Last edited by: 440 SixPak,

Welcome to HTC.com iclee - we're glad you found us!

John - thanks for helping out our new member

Hey iclee,

I researched the book a bit for some places to check. It appears as if fuse number 47 is just for the trailer wiring right turn signal Should be a 15 Amp fuse. Check that.

There is also a black 14-pin connector to the front control module (fuse box) labeled C217. The light green wire is for the right turn signal to the trailer harness.

Does your truck have the 7-way connector located to the left of the license plate? If so, you could check to see if it works there. The pin diagram should be embossed on the door of the connector.

Let me know if this helps and what you find.

Well I checked and nothing all is well (so it appears anyway) I was able to check for continuity from the 14 pin plug and I do have that. Something I did notice is that when I have the left turn signal on I get a click up under the fuse box when I turn the right one on I don't hear it? Do you think that might have something to do with it?

Lee

Do you have access to a multi-meter? I think you said there is no voltage at the wiring connector at the back of the truck. Have you checked it with a meter or are you going on the assumption that the trailer signal is not lighting so there must be no voltage. Does the right trailer running light work (low filiment)? I have seen the connection inside the trailer plug connector go bad from being bent back and forth from plugging and unplugging so sheck the wiring at the connector before the connector, truck side (you will have to expose some wire to do this.) If there is some voltage at the connector check the ground at the trailer light itself. Possibly a bad bulb also. Have you changed left and right side trailer bulbs to see? I know some of this sounds basic but just trying to cover all the bases.

You mentioned you checked continuity from the 14 pin plug... to where? the fuse box or the trailer wiring harness at the back bumper?

I checked from the 14 pin plug C217 back to the 4 wire flat connector for continuity, it's good. I'm sure it's not the trailer because I'm not getting voltage to the 4 wire flat plug or wire on the green wire (right turn) the left and running lights have voltage. The multi meter has been my best friend the past couple days lol. And basic or not all advice is welcome.
Thanks for the shout out SLAMLLC

Oh yeah I forgot to mention that I don't have a 7-way connector to try and test it there. I still fill as though I'm missing something simple but the more I check and the more I am learning I'm starting to wonder.

Thanks again guys for all the advice. Lee

If there is no clicking when you turn on the right turn signal, then it's the relay. The truck itself has no relay/flasher unit for the turn signals, it's a digital circuit. The relay is for the trailer wiring. There are separate relays for left and right. The only thing is, those relays appear to be deep inside the front control module, not the ones you see when you open the lid.

Is your truck still under warranty?

nope, only warranty left is good old me lol

Is it something you think I need to leave to the professionals?

Well, the relay that isn't clicking seems to be located INSIDE the control module. I've never seen one taken apart and wouldn't begin to know how to tell you to do it.

Maybe someone else here happens to have one lying around (it's possible with these guys) and can tell us what it takes to get it apart and where the relays are inside.

I'd hate to tell you something and have you ruin your truck. On the other hand, I'd hate to send you paying someone to do something you could have done yourself.

Hmm, well I think I might call and see how much the pro's will charge. I'll keep you informed and let you know once I get it fixed if that is the problom.
Thanks again for all the help, Lee

I hope it doesn't cost very much... I hope you have a helpful dealer who isn't out just to make a buck.

Update!!!
Well it's been almost 2 months and I still havn't got it fixed. I took it to the (local)dealer which said it was the FCM which had to be special ordered. $417.00 and two months later and still no part. I can't even get them to return my phone calls... Grrrr
I think I'll change dealers once this is taken care of.

Good idea! Hope they figure it out for you soon!

I'm glad my diagnosis was correct. For everything the front control module does, I'm surprised it's not more expensive. I hope you get it straightened out soon.

to the HEMI family Ice. This is why I have a 7yr 85k bumper to bumper warranty 0 deductible. You can get the extended warranty up till the factory 36k warranty runs out.

Iclee,

I have the same problem only with left signal. No current to 7 way plug or 4 way flat. Followed all the way to fuse box. I also have clicking with left signal on but not right signal. Did you ever get your's fixed? If so, could you shed some light on this for me?

Thanks, Chubby