03 expedition eddie bauer- 5.4, non air suspension, 94K miles

I have an issue with the back up lights coming on, staying on, and flickering off and on while driving (forward in drive). I checked the plug on the sensor on the transmission where the linkage is connected. It seems to work fine sitting still in the driveway- on and off when it's supposed to be. Jiggling the linkage and changing gears it seems to work so it acts like it's adjusted ok. Just when it's in motion it has issues. I pulled the fuse as a temporary fix until I can dig into it more so my wife doesn't get a ticket with them coming on intermittently (she just has to be careful backing out of spots and doesn't plan on doing any night time driving between now and the weekend.)

I didn't want to just replace the sensor if it could be something else that is simple like a bad relay- which I couldn't even find in the fuse box (couldn't even find location # 301 like stated in the owners manual). And I do not know how to adjust the new sensor- although I think the haynes manual states how to.

My question: Should I bite the bullet and replace the sensor or try something else? I unplugged the connector and it was clean- no fluid or anything....??? Anything suggestions for something else to try?

Also, any tips in replacing the sensor or setting it? How much do they typically cost?

Thanks in advance!

 

Anyone? Does this sound like a a bad sensor on the transmission or something else?

 

I believe your MLPS is bad on the transmission or it needs to be adjusted this is also called the DTR;

Digital Transmission Range (TR) Sensor

The digital transmission range (TR) sensor is located on the outside of the transmission at the manual lever. The digital TR sensor completes the start circuit in Park and Neutral, the back-up lamp circuit in Reverse and the neutral sense circuit (4x4 only) in Neutral. The digital TR sensor also opens and closes a set of four switches that are monitored by the powertrain control module to determine the position of the manual lever (P, R, N, D, 2, 1).

 

Well I put a new DTR sensor on it and still have the problem. When hitting bumps going down the road the back up lights flicker off and on. When parked in the driveway everything works as it is supposed to. Just hitting bumps on the road make them flicker on.

What else could it be completing the circuit and making them come on?

 

At this point I think you should go under the truck with a dead blor hammer and with the truck in gear bang on various parts of the suspension to get the lights to flicker, all the while checking the wires for rub through signs

 

Thanks for the replies Mel-I thought that would work too. I beat the @#$% out of the frame and underside of the vehicle trying to get them to flicker- while it was in all gear positions. I jumped on the rear, shaking it as best I could with no results. It works fine in the yard and I can only get it to come on going down the road. I even pulled the lights off and tugged on the wires as far as I could follow them.

I will re-wire the backup lights with a switch before I take it to the dealership and get charged a small fortune just for back up lights. Any more suggestions before I rig something up? Any one else ever run across anything like this or is this just a continuation of my great luck?

 

With the minimal amount of light the OEMs put out I'm thinking of mounting a pair of small fog lights in the rear. Or you could go Jamaican and install some driving lights in the rear in case someone follows with their high beams on.

 

The factory towing package wiring harness likely has a short in it. That's the only other place where you're going to get 12 volt power bundled with the backup light switch leg wires. The short might be at the pigtail connectors at the left rear of the vehicle just in front of the rear bumper.

 

Thanks alloro. I will look for it as soon as I get the chance and see if I that's the culprit.

 

Well, after messing with the wiring harness/plug/pigtail thing for the trailer lights and tugging and following wires as far as I could to try to get the lights to come on- they have been working fine???

Would a skinned wire hitting the frame actually complete the circuit to make the back up lights come on while in drive?

I was convinced that it would be the connection at the trailer lights, and it still may be. My next thing it to clean all of the plugs with electrical cleaner to attempt to keep the issue from coming back. We'll see.

 

No, that would cause a short and blow a fuse.