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2003 reverse/back up lights

2K views 27 replies 6 participants last post by  HemiFun05 
#1 ·
I need help my state inspection is due, and I have been searching for an answer to my problem. My 2003 Ram 1500 has no reverse lights, every other light functions as it should but reverse. I checked the fuse it was good, I tried new bulbs no change, I even tried moving the shifter between park and reverse and jiggling it still nothing. I am stumped I had been reading that these trucks use a ipm module and it could be that or the trs sensor on the auto trans. I'm not sure where to check next, if I check the plug at the back of the tailight for a reverse signal which wires do check for voltage? If there is no voltage in reverse at the plug would that be the ipm or trs sensor? I'm sorry for the questions I just need to get this fixed for my inspection.
 
#2 ·
Let me check some schematics and I'll post. My guess its a ground issue.
 
#4 ·
Ok, here's some information to work with.
 

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#6 ·
And here are a couple drawings.
 

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#8 ·
Well here in the Houston-Metro area they do a visual and emission inspection. So if I check the reverse wires (vt/blk and blk) at the taillight plug and there is no voltage when in reverse, then that means it may be the front control module? All the other taillight functions work normal, brake lights, turn signals, hazard lights, just neither reverse light on either side.
 
#9 ·
Here in Virginia backup lights are required. Although they didn't check them last inspection. Red's are of course different, with a 12v ignition wired to the switch and the switch output connected directly to the backup lights with them grounded.
 
#11 ·
Pretty much everything on mine has been changed . If it was me I would trace the backup wire to the TRS switch and check the input to the switch for 12v. If a problem couldn't be detected then it isn't being fed from the IPM. Check the TRS switch for continuity wit gear lever in Reverse. If it has no continuity then it is bad. You can test jump 12v to the backup light wire after the switch and have lights. Or if the TRS switch is good but no 12v, then troubleshoot that or jump 12v to the backup circuit going to the TRS switch and you sould have backup lights when in reverse.
 
#13 ·
The actual switch is internal, you will need to identify the two wires externally.
 
#14 · (Edited)
The plug is located on the drv side. Vt/bk pin6.
Br/lg pin1. These are the two wires of the backup light switch (TRS).
Power comes in on br/lg pin 1 and when lever is in reverse power should be seen on vt/bk pin6 going to backup lights.
 
#16 ·
Yes, that will do it.
 
#18 · (Edited)
Hopefully the original source is still active and it's just a fuse or relay.
 

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#20 ·
I got a new problem now, my high mount cab brake light doesn't work, so couldn't pass inspection. I tried a new bulb no change, tried finding if there was a fuse for it, but didn't see one. The reverse lights and cab brake light are the only thing that doesn't work on this truck, is there a fuse or relay for the cab high mount brake light?
 
#22 ·
The cab brake light is 12v from the IPM and is not controlled by the FCM. The brake light switch is actuall three seperate switches combine together. One of these provide the 12v to the cab brake light. I can look up the wire colors later if you need them. Does the brake light socket have power to it?
 
#26 ·
Well done..
 
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