2G Another reverse light issue thread

[Boostaru]

Hi fellas,

I've searched the forum and checked the majority of common issues that cause our reverse lights to malfunction.

So far:
Checked the reverse switch
checked wiring for power and ground at the harness plugs at the reverse lights
brand new reverse lights
cleaned out the light plugs
cut old wiring and soldered in new ones

The issue:
My reverse lights come on whenever they feel like it when car is in reverse, sometimes it'll come on right away and stay on but other times it'll never come on and occasionally, if i leave the car in reverse the lights would come on few minutes later.

thoughts?

 

[rolltidero]

I know you said you checked the reverse switch. Did you replace it? Mine didn't work at all and fixed my problem after completely replacing the switch. The only other thing I can think of is maybe something is loose in the transmission. I'm not 100% sure how the reverse switch works, but my general understanding is that there is an arm in the transmission that hits the switch when the car is in reverse. If that arm is loose or broken, maybe it's hitting the switch even when the car isn't in reverse. Someone can correct me if I'm wrong but that is my best educated guess.

 

[Boostaru]

I know you said you checked the reverse switch. Did you replace it? Mine didn't work at all and fixed my problem after completely replacing the switch. The only other thing I can think of is maybe something is loose in the transmission. I'm not 100% sure how the reverse switch works, but my general understanding is that there is an arm in the transmission that hits the switch when the car is in reverse. If that arm is loose or broken, maybe it's hitting the switch even when the car isn't in reverse. Someone can correct me if I'm wrong but that is my best educated guess.

I jumped the switch and it's still the same issue. The switch works in a simple manner, it has a little ball that activates the switch once it's in reverse. Bypassing the switch eliminates it from the equation for now.

 

[rolltidero]

I jumped the switch and it's still the same issue. The switch works in a simple manner, it has a little ball that activates the switch once it's in reverse. Bypassing the switch eliminates it from the equation for now.

Oh ok. I'm not really an electrical guy so I wasn't sure. Your reverse lights may be getting power from somewhere else. One of my friends in high school had a lexus and he bought aftermarket LED tail lights and while wiring them up accidentally spliced his reverse lights into his brake lights so his reverse lights came on whenever he hit the brakes. If a PO has done any electrical work, no matter how insignificant and unrelated it may see, I would start there if you already haven't.

 

[1990TSIAWDTALON]

One side of the switch will go to ground, the other side goes to the backup lights. The backup lights should have power to them at all times and wait on the switch to ground in order for them to come on. Make sure the ground side of the switch actually has a good ground by using a multi-meter to check for continuity to ground. You are correct it is a simple ball that makes the switch connection. If someone has put an extra washer under the switch then it isn't pressing the ball in far enough to make the circuit complete to ground so check the switch and see if it has a washer or more than one under it. It should have just one. You can unscrew it and plug it in, then press the ball in to see if the reverse lights come on or not as a simple test. DO NOT overtighten it when you put it back into the trans or you will break it off, they aren't real strong. It just needs to be snug is all. Good luck!

 

[Boostaru]

One side of the switch will go to ground, the other side goes to the backup lights. The backup lights should have power to them at all times and wait on the switch to ground in order for them to come on. Make sure the ground side of the switch actually has a good ground by using a multi-meter to check for continuity to ground. You are correct it is a simple ball that makes the switch connection. If someone has put an extra washer under the switch then it isn't pressing the ball in far enough to make the circuit complete to ground so check the switch and see if it has a washer or more than one under it. It should have just one. You can unscrew it and plug it in, then press the ball in to see if the reverse lights come on or not as a simple test. DO NOT overtighten it when you put it back into the trans or you will break it off, they aren't real strong. It just needs to be snug is all. Good luck!

Yeah, I went through the threads with people having issues with their washer thickness causing the ball to not be pushed in an appropriate manner.

I'm going to dig around some more and make sure that the switch is in fact getting constant power and that grounds are sufficient enough to support proper operation

 

[1990TSIAWDTALON]

Remember, it only grounds the circuit for the reverse lights to come on. The lights should have 12V+ on them already, waiting to see the ground that the switch will provide once the ball is pressed in far enough when you shift into reverse.

 

[dustyboner]

You must be logged in to view this image or video.