Reverse Lights diagnosis?

[Mike Blaszczak]

Hi!

I have a 1999 C4 coupe with a manual transmission. Earlier in the spring, I had the transmission repaired -- 2nd gear replaced and the pinion bearing replaced, too.

Since then, I installed a short-shift kit myself.

Today, I noticed that the back-up lights aren't illuminating. All the gears engage fine, including reverse, so I don't think there's an adjustment problem. I don't know if the lights were working or not before my short-shift installation.

What are the likely causes for the lights not working? Switch wasn't reconnected after tranny work, or the switch is bad, I guess. But could my short-shift installation be causing the problem?

Thanks!

 

[creekman]

Mike,

 

Obviously it's something,  I installed a short shift kit in my '03' and don't remember any wiring attach to the the shifter?  But then again I can't remember what I had for breakfast.  On a rare coincidence have you checked the lamps in the tail light housings....  I doubt that the back up lights are on their own fuse, but have you checked that?

 

Keep us posted even if it means embarrassing yourself...

 

Mitch

[JFP in PA]

It is not on the shifter, it is on the transmission itself:

 

Repairing the 996 backup light switch

[Mike Blaszczak]

23 minutes ago, creekman said:

Obviously it's something,  I installed a short shift kit in my '03' and don't remember any wiring attach to the the shifter? 

 

Obviously! 🙂 The B5 fuse is for the reverse lights, but it's fine. I suppose it's possible that both reverse lights blew, but I don't think it's probable.

Indeed, there's no switch on the shift console -- just the parking brake switch and the switch for the storage box being closed (and the windows, and the courtesy light in the ash tray). My concern is that I haven't adjusted the cables correctly and, in reverse, I'm in some sweet spot that engages reverse gear mechanically, but isn't far enough (or too far?) that the switch on the transmission housing engages.

It that's possible, then I have to take apart the console and adjust the shifter cables again. If that's not possible, then I know I have to get the car in the air, take apart the belly pan, and fuss with the switch.

Is it possible that the reverse gear engages, but the switch isn't activated due to the adjustment of the shift cables?

[JFP in PA]

24 minutes ago, Mike Blaszczak said:

 

Obviously! 🙂 The B5 fuse is for the reverse lights, but it's fine. I suppose it's possible that both reverse lights blew, but I don't think it's probable.

Indeed, there's no switch on the shift console -- just the parking brake switch and the switch for the storage box being closed (and the windows, and the courtesy light in the ash tray). My concern is that I haven't adjusted the cables correctly and, in reverse, I'm in some sweet spot that engages reverse gear mechanically, but isn't far enough (or too far?) that the switch on the transmission housing engages.

It that's possible, then I have to take apart the console and adjust the shifter cables again. If that's not possible, then I know I have to get the car in the air, take apart the belly pan, and fuss with the switch.

Is it possible that the reverse gear engages, but the switch isn't activated due to the adjustment of the shift cables?

 

See my post above...........😉  I'll bet the connector has come off the switch as the shifter has nothing to do with the back up lights, if it were so maladjusted that the gear did not contact the switch, it would pop out of gear every time you tried to back up....

[Mike Blaszczak]

1 hour ago, JFP in PA said:

 

See my post above...........😉 

I know that the switch is on the transmission. That isn't my question.

 

1 hour ago, JFP in PA said:

 

I'll bet the connector has come off the switch as the shifter has nothing to do with the back up lights, if it were so maladjusted that the gear did not contact the switch, it would pop out of gear every time you tried to back up....

Great, thanks. If the shifting cable adjustment isn't a possible cause, I know to focus on the switch itself.

[JFP in PA]

1 hour ago, Mike Blaszczak said:

I know that the switch is on the transmission. That isn't my question.

 

Great, thanks. If the shifting cable adjustment isn't a possible cause, I know to focus on the switch itself.

 

As you had trans work done earlier, it is the obvious place to start as the switch is in a location that is not easy to see if the harness is fully plugged in.

[Mike Blaszczak]

A replacement switch arrived from Pelican and I had some time to get under the car yesterday. 

 

The existing switch was tightly installed and plugged-in. I replaced it with the new switch and the lights began working when I shifted into reverse.

 

Thing is, the old switch tested fine: continuity when pressed, open when not pressed. I can only guess that the old switch was fine, but its plunger was not making physical contact with the selector rod inside the transmission.