No reverse light 2007

[exalteduser]

07 caravan sxt 3.3
No reverse lights

-bulbs arent burned out
-looked in fuse panel and no particular fuse is named for reverse lights but there is nothing blown i checked them all
- ive read about a backup light switch on the tranny but only on 2002 and older models i cant find info for my 2007. scratching head....

[jpb53]

Here's a wiring diagram.

[RIP]

The backup light switch is the Transmission Range Sensor or TRS. It's located inside the transmission. There is an external connector. Try wiggling the gear shift. Lights come on?

[exalteduser]

i just tried the wiggling the gear lever to no avail with the wife behind van looking for signs of light. i will get on testing the grounds although the "sockets" arent really sockets.

on a side not does anyone sell that TRS sensor? didnt see it on autozone website

[hundahunta]

possible bcm.....try ground pin 37 at the pcm to bypass the trs. The fcm busses the message to the bcm. The bcm turns on the lamp...

[exalteduser]

i find it hard to believe a bcm could be bad with the only symptom being reverse lights.

there is 1 other thing to note the van got t-boned a month or 2 ago, (barely) just a caved in slider door on passenger side and its fixed now. is there a chance the wires run near there and are grounding out or got pinched or something? it seems that each side is ran separatly so i dont know how that would affect both. I dont know what the deal is.

I will say, to hell with new vehicles, the companies try to make them so people cant fix them without grabbing their ankles at the dealer and i refuse to do that. i will just live without them if it comes to that

[RIP]

Originally Posted by hundahunta

possible bcm.....try ground pin 37 at the pcm to bypass the trs. The fcm busses the message to the bcm. The bcm turns on the lamp...

...or disconnect the TRS connector and ground contact #9. Will accomplish the same (bypass TRS) but probably an easier access. Just be damned sure you are grounding contact #9 as messing with PCM inputs can be risky. While there check the TRS connector for damaged/bent/corroded contacts.

I checked a few of my regular sites for the TRS. No luck.

There have been complaints of loosing the instruments, stalling, and other electrical ghosts caused by a chaffed wire harness in the bottom of the sliding doors. Data bus wires would short against the frame. There was even a safety recall for newer model 5th generation vans for it. Claimed it was a fire hazard. I doubt that would cause just a problem with reverse lights.

Gotta agree. Why route power through that many components for a simple reverse light circuit? A switch, some wire, and the light sockets would work just fine. I can picture the engineers sitting around a table puffin cigars laughing and saying, now they HAVE to bring them to the dealership. We gotem by the short curlies boys!

[hundahunta]

as cars become more electronically controlled it is harder for an individual to diagnose their own vehicles. Take the reverse light circuit for example, just imagine if this circuit was not controlled by a module (bcm, fcm, etcc.). You would need a wire from the switch to the reverse lamps, to the tcm, to the pcm and cluster. That's a lot of wires for 1 circuit, imagine how many circuits a vehicle has, it would take miles of wires for a vehicle's electronics. The engineers started to multiplex wires and bus the messages to combat this issue. I understand the frustration of the people, just imagine doing this day in and day out.

[exalteduser]

i see 3 to 4 things on the top of the tranny that are some sort of sensor or wire harness how would i be sure which is the trs?

[RIP]

Originally Posted by hundahunta

as cars become more electronically controlled it is harder for an individual to diagnose their own vehicles. Take the reverse light circuit for example, just imagine if this circuit was not controlled by a module (bcm, fcm, etcc.). You would need a wire from the switch to the reverse lamps, to the tcm, to the pcm and cluster. That's a lot of wires for 1 circuit, imagine how many circuits a vehicle has, it would take miles of wires for a vehicle's electronics. The engineers started to multiplex wires and bus the messages to combat this issue. I understand the frustration of the people, just imagine doing this day in and day out.

I hear ya. Me? I'd stick a switch in the gear shift mechanism, wire, lights, done. Thats all a reverse lights circuit deserves. In any case, many would gladly accept that extra 30 pounds of wire, yours truely included. Somehow the old KISS approach has gone by the wayside. Ok now back to reality.

[RIP]

Originally Posted by exalteduser

i see 3 to 4 things on the top of the tranny that are some sort of sensor or wire harness how would i be sure which is the trs?

Look for the connector that sits verticle on the right side front. All others are horizontal. Should have in the neighborhood of 10 wires.

[jpb53]

Tranny wiring diagram.

[exalteduser]

A valuable lesson has been learned. Just because the filaments arent broken or damaged, doesnt mean the bulb Isnt dead. my last ditch effort was to change them anyway just to see and they work. Sorry to waste your time.

On a side note they have plastic base instead of screw in kind so maybe something went wrong inside there. Guess i should have done that first /facepalm

[RIP]

Bit by the basics bug. We've all been there. Happy to hear it was an easy fix.