I don't know what year Dodge truck you have but for a good number of years the back up light switch on a Dodge was threaded into the transmission, if it was an automatic. The same switch served as the neutral safety switch.
It is on the same circuit as the brake lights, but if they are not working, and the bulbs are good your switch needs cleaning or adjustment.
Attempt this first since the switch costs nearly $300 bucks.
On the passengers side of the trans just behind the bell housing there is a fan shaped switch, loosen the 12mm bolt ( smaller of the two, and rotate the switch while a friend checks the lights. this problem is usually accompanied by an occasional inability to start the vehicle, but can be cured by jiggling the shifter.
While adjusting the switch make sure that the vehicle will start in park as well, remember to block the wheels while testing the back up lights, engine off, key in run but not start, shifter in reverse, move switch until lights come on.
Once you find this spot, hold it in place and have your helper check to make sure it will start. This may take several tries to get both working correctly.
If you have no luck the switch may be dirty, this happens a lot. Hold the post to the bottom large bolt still while you loosen the nut, then remove it, then remove the 12mm adjusting bolt on top, remove the wire connector and pull the switch away, remove the bolts on the switch and separate the halves, use electrical contact cleaner and maybe some q-tips to clean all the copper connections completely apply di-electric grease and reassemble, refit to the trans and readjust so all functions work, this switch controls back up and start safety.
Caution! always hold that bottom bolt while tightening the large nut, this is connected to the gear adjuster and you could damage the internals if it isn't secured while you do it.
its on the transmission close to the driver side
Dodges are good for blowing fuses. If that is not it, the fan switch might need replaced.
Jeeps do not use inertia switches.
Most Likely it is a 45RFE. The 2003 and on have a 42RLE. The 45 will handle more torque. It was used in Dodge trucks and Grand Cherokee.
This comes to a great many of issues and questions. First are they both the same transmission, is the Dakota ment to have 4WD, what is your fabricating cababilites... so on and so forth. Personal suggestion, don't bother, but if you are determined you can make anything fit anywhere.
A neutral safety switch is located on a steering column or center console depending on where your gear selector is placed, and is for automatic transmissions. the clutch safety switch is located near the floor board on the firewall where the clutch petal meets it when depressed. in both cases these switch brackets can get bent or loosened pull forward on a bent bracket, or tighten the strap and adjust in both cases to ensure the lever is engaging this button.
The backup light switch is mounted on the transmission casing.
its on the front of the transmission, near the trans pan
The backup light switch is located on the side of the transmission. It has two wires coming off of it but they are probably covered in wire wrap.
Where it is exactly I do not know suffice it to say that it is somewhere on the transmission.
it is located under hood in relay and fuse holder. right by driver front fender
Most likely on the back left of the transmission, right above the pan.
Most likely on the back left of the transmission, right above the pan.
The backup sensor is inside the transmission.
I don't know what engine/transmission you have, but on my wiring diagrams for the Magnum V8's / 46RE transmissions, the reverse switch is part of the Park/Neutral switch on the left side of the transmission, purple with a black stripe.
There is no relay for the backup lights. The circuit is powered by the keyswitch, runs thru a 10 amp fuse on the interior fuse block, then goes through a switch mounted on the transmission, and on to the lights. The switch is on the front of the manual transmission, and on the lower front of the automatic.
More than likely you will need to replace the backup light switch on the transmission case.
I believe it is located at the base of the steering column and works in connection with the gear shift lever. If not, then it will be a separate switch screwed into the transmission case.