NSS / TRS Serviced Today- Backup Lights-YES!!!

I carefully followed the pictorial write up on the forums for servicing the Neutral Safety Switch, correctly called the Transmission Range Sensor, or TRS, as it is a multifunction device doing more than just locking out engine start function when not in neutral or park.

It came off the transmission with no problem. The big nut was loose. I wonder if that is cause of the "no back up lights" condition others have reported. The way the switch works, the big nut holds the moving arm and its contacts against the fixed contacts in the switch case. Just a thought. Maybe all is needed is a nut tightening to get the back up lights to work. That nut only gets a gentle snug. Not the big cinch its size would suggest. The bendable tabs keep it from coming loose.

Anyway, I removed, disassembled, and cleaned the whole thing just as a preventive maintenance task. About a half hour out and an hour cleaning and reinstall. Easy to do. Took more time to get to the three zip ties on the cable harness than it did to get the thing out.

Magic tool for removing it from the transmission case was a door panel removal tool. It is the bent fork tool great for prying anything.

Calibration tip: Before reinstalling, from top of the engine bay, I connected the cable harness. Put ign swith to run (no engine start), put shift lever in R. Then rotated NSS/TRS shaft to find when Reverse lights came on. Centered the shaft on that event and scribed the shaft and case for later alignment. Turned off ign switch. Lowered switch through engine bay and secured it back onto the transmission from below. Slightly snugged the alignment bolt and rotated the assy to align the scribe marks. Turned ign switch back to run with shift lever in R. Verified Reverse lights came on. Turned power off. Finished tightening alignment bolt. Installed rubber washer, tab washer and big nut to right torque. Bent tabs to secure big nut. Re-verified proper alignment by starting and testing reverse lights and other transmission modes. All OK.

Added not of caution: Where the wires exit the switch housing there is also a small rubber tube about an inch long. This is an air vent. Now, for those who like to swamp their vehicle pretty deep, you may be getting water above this vent height and introducing water into the switch assy. Not good. Can lead to no starts, and no reverse lights as well as other transmission related mysteries. Solution would be to replace that stub of a tube with a long one ending high in the engine bay. Just a suggestion.

Happy Trails.

I never even thought about that damn tube when I took mine out. I went of of GOJEEPs forum. My rig sees a lot of swamp. I'll take a look at it this weekend. Do you happen to know what size the tube is?

Glad the vent tube came to your attention. Fix looks easy. Tube is about 1/8 inch i.d. Has a little metal cap on it. You should be able to replace it right on the vehicle if the exhaust is not too close.

It is probably concealed inside the ribbed plastic wire shield tube, unless that has deteriorated or been previously removed.

If there is any suspicion of TRS malfunction, just take the whole switch off and service it. It is good PM. You don't want to create your own bad luck by skipping a two hour maintenance task and then ruin a whole weekend with a jeep that does not want to play hard and get you home.

Let us know how it all goes.

Happytrails said:

Glad the vent tube came to your attention. Fix looks easy. Tube is about 1/8 inch i.d. Has a little metal cap on it. You should be able to replace it right on the vehicle if the exhaust is not too close.

It is probably concealed inside the ribbed plastic wire shield tube, unless that has deteriorated or been previously removed.

If there is any suspicion of TRS malfunction, just take the whole switch off and service it. It is good PM. You don't want to create your own bad luck by skipping a two hour maintenance task and then ruin a whole weekend with a jeep that does not want to play hard and get you home.

Let us know how it all goes.

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I already disassembled/cleaned/sanded/greased/ and reassembled my NSS or TRS, with good results. I just never occurred to me what that tube was. Hell, it's identical to all of the other stock vent tubes on mine save for the metal cap where all of the others are plastic.