Trailer Lighting Module Fault. Where is the Module?

[FerdRanger]

Got a “Trailer Lighting Module Fault See (useless) Manual” message on the dashed followed by ”Trailer Right Turn Lamps Fault Check Lamps”


I don’t have any TBC so I’m NOT talking about the trailer brake control module

tried two different 1157 bulbs and both work when truck is locked and unlocked with FOB so I fear its the lighting module

anyone know where it is?

I searched for the part and came up with LJ6Z19H332A that costs about $135, but shows its in the passenger compartment of a sedan??

I’m trying to decide if it’s DIY or a dealer / extended warranty job

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[RangerBill]

Got a “Trailer Lighting Module Fault See (useless) Manual” message on the dashed followed by ”Trailer Right Turn Lamps Fault Check Lamps”


I don’t have any TBC so I’m NOT talking about the trailer brake control module

tried two different 1157 bulbs and both work when truck is locked and unlocked with FOB so I fear its the lighting module

anyone know where it is?

I searched for the part and came up with LJ6Z19H332A that costs about $135, but shows its in the passenger compartment of a sedan??

I’m trying to decide if it’s DIY or a dealer / extended warranty job

The TRM (trailer module) is located up under the passenger side of the dash. It has a 12 pin connector, a 2 pin connector, and a 4 pin connector. Are you saying that the right turn bulb on your trailer lights when you lock the truck, but doesn't light when the right turn signal is on?

 

[airline tech]

These relays have been omitted and full control is from the TRM.

 

[FerdRanger]

The TRM (trailer module) is located up under the passenger side of the dash. It has a 12 pin connector, a 2 pin connector, and a 4 pin connector. Are you saying that the right turn bulb on your trailer lights when you lock the truck, but doesn't light when the right turn signal is on?

that is correct… right trailer bulb is getting power when I use the FOB, but using the turn signal lever causes the fault message and dash indicator light hyper flashes whistle the bulb does nothing

without the trailer, works as expected

sounding like someone who fits under a dash job…no?

 

[FerdRanger]

These relays have been omitted and full control is from the TRM.

lol

appreciate you, but I can’t read music or schematics

 

[RangerBill]

that is correct… right trailer bulb is getting power when I use the FOB, but using the turn signal lever causes the fault message and dash indicator light hyper flashes whistle the bulb does nothing

without the trailer, works as expected

sounding like someone who fits under a dash job…no?

It might be a resistive connection to the trailer turn signal wiring or in the truck. Are both trailer turn signal bulbs the same brilliance when you lock the truck and they flash? If the right one is dimmer, then there is a poor connection in the wiring. Do you have another trailer that you can connect to your truck for a test? This would narrow down the problem to the truck or trailer wiring.

 

[FerdRanger]

It might be a resistive connection to the trailer turn signal wiring or in the truck. Are both trailer turn signal bulbs the same brilliance when you lock the truck and they flash? If the right one is dimmer, then there is a poor connection in the wiring. Do you have another trailer that you can connect to your truck for a test? This would narrow down the problem to the truck or trailer wiring.

left trailer signal works fine
using the fob, both sides bulb’s turn and brake filaments light up
right may be a bit dimmer…hard to tell

No access to another trailer, but that would be a good check

he goes in thursday for moderate oil drips after having the dealer do the “works” so I’ll see what they say

was trying to get intel before that and you’ve given me great info

thanks

 

[RangerBill]

left trailer signal works fine
using the fob, both sides bulb’s turn and brake filaments light up
right may be a bit dimmer…hard to tell

No access to another trailer, but that would be a good check

he goes in thursday for moderate oil drips after having the dealer do the “works” so I’ll see what they say

was trying to get intel before that and you’ve given me great info

thanks

You're welcome. If the right bulb is dimmer than the left, that could trigger your fault message, as the trailer module senses current and if it is low (like due to a bad connection), it will trigger this message.

 

[airline tech]

For the Truck Side, you may try to pull and inspect 3 ea connectors
C405 & C4099 & C422

If its a bad connection on the Truck Side, its a high probability of a dirty corroded connection on one of the 3 connectors below.

C405 - RH Stop/Turn = Pin #15

C4099 - Back side of 7-Pin Connector
RH Turn = Pin #4

C422 - RH Turn = Pin #17

 

[jflogerzi]

check fuse? there are different fuses for turn signals.

 

[airline tech]

check fuse? there are different fuses for turn signals.

Fuse #87 feeds both LH & RH Stop / Turn for the Trailer Lights and controlled by the TRMtruck

If you are referencing Fuse 56 & 63 and the relays, so far no one has reported that they have those relays and fuses installed.
The wiring diagram shows them but they are for a truck that does not have the TRM installed, so far I have not seen a truck that does not have it, which is why I edited the diagram to show how its actually wired.

 

[jflogerzi]

I just remembered I had this exact issue but in reverse. running lights were not working but turn signals were. replaced the fuse and bam working again. It was the PiTA one in the engine on the underside.

 

[FerdRanger]

For the Truck Side, you may try to pull and inspect 3 ea connectors
C405 & C4099 & C422

If its a bad connection on the Truck Side, its a high probability of a dirty corroded connection on one of the 3 connectors below.

C405 - RH Stop/Turn = Pin #15

C4099 - Back side of 7-Pin Connector
RH Turn = Pin #4

C422 - RH Turn = Pin #17

that is helpful, wish I had a lift.

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