QuestionQUESTION: i have a 2002 dodge grand caravan sport 3.3 ltr 4 speed automatic 180 horse power van. my problem is when i shift in reverse my back up lights don't come on. so far i've replace the following things. fuse and relay center, neutral safely switch,the body module in the left wheel well area, and the rear light assembly left and right. do you have any clues to my drama
ANSWER: I just found this question in the Question pool so I'll do my best to help you. I'm a little confused about which parts you've replaced. Specifically the neutral safety switch. Chrysler stopped using those switches on their electronic traansmissions in 1999. Since then they use what is called a Transmission Range Sensor which is located inside the transmission and is not something that the average person can easily replace. There is no way to test this sensors outputs without the use of Chryslers DRB III scan tool or another high end scan tool. Since you've covered all the other possibilities you may want to consider bringing the van to a reputable repair shop for a proper diagnosis.
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QUESTION: i just saw a picture of a transmission range sensor and it is the same part that i replaced already in which it was called the neutral safety switch.any other ideas.
ANSWER: Unfortunately this system is no longer as simple as it should be. The TRS only senses what position the shift arm is in through a series of voltage dropping resistors, that signal is then received by the Front Control Module which then sends the information out on the vehicles communication network to be used by any number of other modules that need to know what gear the vehicle is in. With that said, the only way to diagnose your problem would be to use Chryslers DRB III or another high powered electronic diagnostic tool.
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QUESTION: Can it be a wiring problem
AnswerThe simple answer is, yes, it could be wiring related. There are only two wires that you could check. The first would be the wire from terminal 1 of the TRS wiring connector to the underhood fuse panels tan 20 way connector cavity 4. Disconnect both the TRS and fuse box connector and using a DVOM set to read ohms. Check the wire, which will be Dark Green with a White tracer. for continuity. You should read between 0 and 5 ohms of resistance. If not the you will need to find the broken wire somewhere in the wiring harness. The next wire to check will be between the Body control Module and the reverse lamps. You will need to disconnect the Black/Green Body control module connector, which is located on the firewall above the drivers left foot, and apply battery voltage to cavity 9, the wire will be White with a Green tracer. If the lights do not light then you will have to trace down the broken wire between the BCM and the rear lights. If both the above test pass there is a problem with either the BCM, the fuse box assembly or the communication between the two. Good luck, that's all the info I have left to give you.
