I have a 2000 F150 4x4 with a 5.4L Triton V-8. I also have an automatic transmission (U-code 4R70W) w/overdrive. I've recently noticed that my reverse lights were not illuminating when I put my truck in reverse. I've checked the fuse(#5 in the passenger compartment fuse panel) as well as all the other fuses in that panel, and they all show 12v across both fuse terminals. I also checked all the fuses in the power distribution bock and all checked out ok as well. I pulled the rear tail light assembly and both bulbs are in working order. When placing the the ignition in the run position and the vehicle in reverse, I tested the voltage at the reverse light socket (BK-PK wire) with a multimeter and it wasn't reading any voltage. The socket also had a good ground connection (continuity with chassis) . So i ruled out a loose ground wire as the culprit. After this I tested the output from the DTR sensor on the passenger side of the transmission (DG-YE output wire) and the wire wasn't reading any voltage. This wire is instead going to ground when the shifter is placed in reverse. It's my understanding that this wire should be sending 12v to the the BK-PK wire that actives the reverse lights. Could this be a faulty DTR sensor or am I overlooking some other cause? The vehicle will only start when the shifter is in "P", so it seems that the DTR is working properly, but could the sensor still cause the reverse lights not to work? Any help with this will be greatly appreciated!