Hello,
my left rear brake light for the trailer does not work but the left brake light on the truck does work...

I have trailer towing package.. both the 4 pin and 7 pin has the same problem. and both trailer brake light fuses are good on the truck.

I have had little luck finding a wiring diagram for my 04 .. mainly for the trailer towing option

the right brake light does work on truck and trailer. as does the turn signal.

Help.

 

Bad bulb? Did you check for voltage at the trailer brake light? Are you getting voltage directly at the truck connector?

 

No voltage at 4 pin or 7 pin for left brake light. but right is OK.

I am a retired auto mechanic, I do know something about wiring .. but without a wiring diagram. I am getting no where.

the voltage was tested with AND without trailer connected.

I guess I should add.. I got truck NEW... never had a trailer connected to truck.
04 Ram 1500 2 wheel drive, V6 5 speed manual, 355 true-loc. trailer towing package. 39,000 miles and never wrecked or had electrical trouble.

 

My 04 has the same problem. It's the IPM that is crap.
Last I checked, they were 6 months back ordered.
I ended up just rewiring the trailer lights bypassing the IPM.

 

Thanks, that is what I am about to do today..
I picked up the type that takes power from the truck battery.. as not ADD extra load to IPM.

 

You might want to try resetting the fcm, as the lighting systems are fed and controlled by that. Disconnect the battery, turn on the headlights to drain residual, reverse.

 

I do not think that will work,

the head lights are controlled by the computer. so removing the battery cable the computer will shutdown and NOT turn on the head light circuit.
but I did disconnect the battery cable and it was OFF overnight.. just because it was late,

No help. I cut all light wires to trailer under truck, and removed 3 fuses from fuse box, trailer left and trailer right and trailer park lamp.
install powered coupler. I am now good to go.

 

You may want to try locating another FCM for the future as the left turn is often a symptom of the fcm going south, at which point you won't have the aforementioned headlights and most of the chassis powered components.

 

Thanks, I had to replace both front wheel bearing yesterday.. 39,000 miles .
for a truck that is well treated and garaged.. this thing is turning into ########.

 

Had the left trailer signal issue on a 2003 Ram. Installed a Modulite 119190 unit and picked up input feeds from truck tail lights in wiring harness. Spliced output signals into trailer tow connector. Worked well.