Reverse Lights Not working

[m7x3r]

Hi everyone,

I was thinking about posting this in the transmission section because I really believe the cause of the problem is from the transmission, but since it's the reverse lights not working I have decided to post it here. Now I have done some research on why my reverse lights not working aside from the usual checking of bulbs and fuses and what not there was one thread for a gentleman who was swapping his tranny from automatic to manual and putting in a KLZE but it still didn't explain why the reverse lights wouldn't work.

Now my bulbs are fine the reverse lights were working at one point and one day I was doing some work under the hood and I happened to knock down one of the wires connected to the transmission reverse sensor which is located directly below the MAF on the tranny itself. since the wire was cut from the sensor itself it wasn't possible to rewire it or re soldier it. So I wend down to the junkyard and found a newer mx-3 94 and up models, mine is a 92 GS with a KLZE motor. Now I got the sensor out of that one and installed it on the new re-wired the two wires but my reverse lights still don't come on I tried the 2 wires both ways but either way I wired them my reverse lights still won't come on. Does anyone know the cause to this or could help me narrow down what could be the cause and how to resolve this. I really can't think of any thing else besides the sensor on the tranny since the bulbs were working at one point!!! Thank you in advance.

[Ryan]

Did you check the fuses AFTER you replaced the sensor? The ECM inputs a voltage to the sensor, looking for ground. If you accidentally let the one leads hit ground, or shorted them, you may have blown a fuse.

Any other symptoms?

Does your junkyard sensor even work?

[Sleeper6]

So just randomly are the 94+sensors different from 93 down? Just bc I know the dashes and distys are so I could see a silly sensor being the same way.

[Ryan]

I imagine they're the same. The trans changed generation somewhere between 93 and 96, but that only involved the synchromesh system, IIRC.

[m7x3r]

Hey Ryan,

I am not sure if it works i pulled it out of the car it was junked i assumed it should but when i was putting it into the tranny i forgot the washer and I had issues, my shifter want go into reverse even if the car is off. and it seemed when we loosened the sensor a bit shifter goes into reverse. Anyways found the washer put it on tightened hard and we were good to go...


But I am not sure what fuse I am suppose to check I am missing few on my GS i assumed they only were used on the SE for extra stuff like ABS or heated seats or something underneath the dash and big fuses in the engine bay are only a few and they're from what I quickly recall for fan coolant or something not too sure now but I am assuming the fuse u're telling me to check would be underneath the dash ...another thing the other day i was underneath the hoist and i was directly under the tranny and saw another sensor looking like plug thingy with wires coming out except it's on the other side of the tranny the side closer to the firewall amost right next to your downpipe but they looked fine and i only had the problem ever since the wire was completely cut in the past they used to work on and off it seemed as the car shifted or went over bumps and I thought it was loose wires in the back but i took out my tail lights checked all wires looked okay put it back then i see this wire coming off the tranny and it was barely hanging..... so later when it was completely torn out i figured it had to be that causing my reverse lights not to work but still even after putting a new plug in ... the wires might have grounded somewhere or touched each other at one point as i was putting it in and wiring it up... i'll go have a look now at all my fuses

thanks again

[Ryan]

The other sensor is the neutral switch. Used by the PCM to lower the idle, and it cancels cruise.

The sensor should read open when not in reverse (infinite resistance), and a few ohms when in reverse, I forget the exact figure. 380 sounds familiar though, but check the manuals.

Check you're getting ground on one pin, and some voltage at the other... either 5ish or 12 ish...

[m7x3r]

okay so still not working I checked all fuses underneath the dash they were all okay and under the hood where else could there be i don't really have a volt meter but what else do you think might not make your reverse lights work besides that switch

[Ryan]

Well, you can do about 0 electrical diagnostics without a multimeter.

It could be a million things from a broken wire to a broken switch.

[m7x3r]

Thanks Ryan you're pretty much right but what I did is jumped the two wires together by connecting them to each other and closing the loop i guess... and sure enough the reverse lights came on but i joined them after the switch of course so I am assuming the one i pulled from the junkyard is no good either mazda dealership would be my only option and i think they go for about 30 or so bux ... so if i put the new one in and resolves it, i guess that's our RFO...