I was out of town, then I got in the truck one morning and got a "lamp out" indicator on the dash and both turn signals would flash rapidly when energized. I figured no big deal, it's just a burned out bulb. I wish it was that simple.

But this is what I found:
Rears - left turn signal is out, left brake light is out. right turn signal (flashes fast) and right brake light works. Third brake light works. All trailer light functions work.
Fronts - both turn signals are out, left headlight is out. both high beams work.

All bulbs are good, and after probing bulb sockets AND terminal connectors with a test light, there is no current in the lights that don't work, so the problem is not bulbs nor bulb sockets.

I checked ALL fuses in the PCM but all are ok. I could not find a dedicated fuse for the turn signals, but again I removed all fuses and they checked out ok, so if there is a fuse for the signals that is in a shared circuit with something else, that fuse is probably also ok. There is a pair of relays for the trailer turn signals and they are ok, but then after probing the trailer socket, trailer lights are ok anyway, so regular turn signals do not use those relays.

I've already spent several hours diagnosing this problem, but now I've run out of ideas.

I've read about two members here that described the exact same issues a few months back, I've sent them both a pm, but have gotten no response. I'm hoping they've worked out the issue by now.

 

may be your multifumction turn signal switch in you steering column needs replaceing

 

Diesel builder might be right I know there is a recall on the 2006 Rams for a malfunctioning multi function switch. Not sure on any other years but that does sound like some of the problems that the switch can cause.

 

That does not make sense. If the switch was bad, it would cause all turn signal bulbs to malfunction, not just some of them. And both turn signal indicators work, although they flash rapidly, which means that the turn signal lever is doing what it's supposed to. The left brake light went out at the same time, which should have nothing to do with the multifunction switch.
I heard the turn signals are controlled by the cluster. I also heard that the turn signals and other lighting functions are controlled by the FCM.
If anyone with the same issue can shed some light on this, it would be of great help.
I really don't want to take this issue to the steeler.

 

I don't remember if the 03 is the same but you might try unhooking both batteries for an hour or so then when you hook them back up make sure all battery cables have tight and clean connections. I've heard of the FCM locking up on some of the 3rd gens and this cleared it up.

 

I have a 03 diesel - loaded. First lost left rear door lock, rt P/W, window lock out, heated seats , trailer connect......................

The brilliant designers did not protect the underside of the Power Distribution Center ( Fuse Box and relay center ) and all the crap/wet was able to hit the underside and birth "green death".

The replacement for this unit now has.....you guessed it...a bottom cover. I am going to install mine this week and intend on spraying down the inside well and packing the connectors before I put the cover on.

The tiny white parts decal (against the mounting side - opposite the power lead end) has # P56049019AF. The update # which includes the bottom is 6800 5474 AA. I got mine through Bobby at RT Partsco - FLA about $350 plus shipping - best price out there!

There was a post on home repair but the studied it and decided I wasn't good enough at soldering etc

Hope this helps