Backup light bulbs are good/ fuse is good, but they don't work. I've got an FSM and I'm still confused. The automatic transmission doesn't show a reverse switch. All I can find is the power-out diagram that shows power to the reverse solenoid and to the backup lights from the front control module. Where does the input come from? I searched first and didn't find anything.

 

I have the same problem. I talked to our parts guy at our local dodge dealer who is one of my customers and to a tranny shop. It's integrated into the tranny and has to be taken out to replace the unit that tells the truck that its in reverse and to power the lights up. I installed a switch and just use it when i need it. But thanks to the body shop that fixed my truck my license plate frame from v-leds is dead. So i'm working on another setup for backups

 

Thanks for the info. I did some more digging in the FSM after I posted this. The B+ power for the back up lamps is at pin #7 on connector C5 at the integrated power module (fuse box). It goes from there to pin #27 on another connector that's plugged into the "front control module". I suspect the signal from the transmission travels over the CAN-bus from the transmission module to the front control module and the front control module powers the circuit from the fuse, via an internal solid state relay. I intend to do a continuity check on the wiring from the module to C5 and from C5 to the reverse lamps to make sure the wire isn't broken, but I'm not optimistic. The fuse box has to be lifted out of it's holder to get to C5, so it'll take some time.

I did notice that connector C1 has a power out to the transmission reverse solenoid. That output must still be good because the truck still backs up! If I don't find a broken wire, I'll splice a lead to the reverse solenoid B+ output and use it to drive a relay to operate the backup lights.

Then again, I may take it to the dealer to check diagnostic codes first. I don't have a CEL or any alarms on my dash but something like this may not show up without polling the CAN-bus network....,

 

Does anyone know how to get at the reverse switch? Or is it inside the tranny itself? It's not mentioned in the dealer service manual.

I am having the same problem, the reverse lights turn on for about 10 seconds then shut off.

Has anyone resolved this issue without just installing a manual switch?

 

I know my switch is somehow attached to my shifter or gear box. I can toggle it on and off by giving a light tap into reverse without putting it in gear. Hope that helps assuming yours is stick shift.

 

The manual transmission has a reverse switch mounted on it that can be replaced. On an auto, the "range" switch on the transmission is connected to the TCM, which then broadcasts the gear info to the display via the slow can-bus and to the PCM via the fast can-bus. The range switch and TCM are working because the gear info is displayed on the dash.

I think I figured out what happened. The previous owner mounted a Lear cap with a high mounted brake/reverse light. I think he probably grounded it and burned up the solid state relay in the PCM that turns on the backup lights. The only OEM solution would be to replace the whole PCM controller and I'm not going there. I still haven't done anything about it a 1.5 year later! LOL..., I think I'll mount a momentary switch on the dash that I can hold down while I'm backing up. If I use a toggle, I'd be driving around with the reverse lights on all the time!

 

How about a backup alert in addition to the toggle switch? Something like http://www.zoro.com/g/00028991/k-G02...z8oRoCEDHw_wcB (note: JUST an example! Not saying to buy that one, but not saying to NOT buy that one ...)

RwP

 

This is a follow up to my backup light problem. I lost my password to my "djsilver" account, the "reset password" doesn't work and the webmaster hasn't answered my request for help, so I registered again as djsilverjohnson.

I found the problem; My truck wasn't equipped with the factory tow package. The previous owner had a factory "Mopar" wiring harness installed to provide a 7-pin connector at the back of the truck. The factory part number is 82209045. The harness has a T-connection that plugs in between the male and female halves of connector C106 in the wiring bundle that goes to the rear of the truck. C106 is located behind the mud-flap at the rear edge of the drivers side front fender-well. The pin-outs are incorrect on the Mopar T-connection. It has the reverse light power feed swapped with a ground wire. That causes the white/light green power wire for the backup lights to be grounded all the time.

I had given up on why the backup lights didn't work and was preparing to install a toggle switch and beeper for me to operate them manually. I cut the white/light green backup wire loose from the connector on the fusebox/front control module, then pulled both backup light bulbs. When I check the wire, I realized it was grounded. I traced the wire to the harness bundle and found the connector problem. I've unplugged the Mopar tow-harness and the ground went away. My truck is in use for a few days, but when I get it back, I'll reconnect the power wire to the original plug under the hood and see if they work (or if the grounded wire killed the relay in the Front control module) If it did, I'll proceed with my manual toggle switch. I'll post an update when I'm finished.