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reverse lights stopped working

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I've noticed that both of my reverse lights have recently stopped working (RHD, 99 model, 996 C4 coupe, manual) and I wondered if anyone's had the same thing happen, or what I can check myself before getting Porsche to look at it. I've confirmed that the rear left side reverse bulb is still OK by plugging it into the indicator bulb holder.

The only thing I've found in the forums is this recent topic entitled "Are any of these the reverse wire sensor?"


I assume there's a wire from the gearshift to the box under the seat on the left, and then the signal is taken from there to the lights? Which wire is leading into the control box -- from the gearshift or out to the lights, or doesn't it work like that?

BTW, does the engine have to be running to activate the reverse lights, or does having the ignition on and the gearshift in reverse enough?

Thanks for any info you can provide!

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  • Admin

Have you had your transmission out lately? Like for an RMS replacement?

In at least a couple of cases dealers have forgotten to reconnect the reverse switch wires after an RMS replacement. If not, check the fuses (B5) and the wires (loose or disconnected).

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Thanks Loren.

The car has never had an RMS replacement that I know of, but the reverse lights were definitely working a month or two ago, plus it passed the UK's yearly MOT test and a full Porsche inspection in February before I bought it.

I've checked the fuse and it's fine, but I've tried engaging reverse while the car is parked a lot of times over the last few days and both reverse lights do come on about 30-40% of the time, but it is very much intermittent. I can shift it in and out of reverse 10 times and the lights won't come on, no matter how I put it in reverse (slow, fast, pushing lightly past the spring, pushing hard, pushing far to the left or not etc etc), then they'll suddenly start working several times in a row.

Which wires were you suggesting to check that could be loose?


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  • Moderators

If you have a problem with both reverse light not working and both bulbs are NEW then this is a switch on the transmission that triggers when you select reverse. You get confusing when you start to switch bulbs. Put 2 new bulbs in the socket and make sure it is the reverse light bulbs you replaced. No glow then it might be the switch on the transmission.

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To clarify my previous posts: the bulbs aren't new, but I only temporarily put the reverse bulb in the indicator holder then operated my left indicators to ensure the reverse bulb was OK. This told me the reverse bulbs were OK and that it was a switching problem elsewhere. From further testing since my first post I've confirmed that sometimes I can get the reverse lights working (either both or neither come on).

Basically it's an intermittent fault somewhere in the switching when reverse is engaged.

Where is the reverse switch located on the transmission?


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  • Moderators

I had another car that did the same thing and I replaced the reverse switch on the transmission. Sometimes the reverse lights worked and sometimes they did not.

It is only because of a switch that a Porsche with a manual transmission knows you are in reverse. Switches go bad sometimes.

There is a guy on rennlist with a 996 and he had the same problem, solved by replacing the transmission switch. Said it was made by an American company, like GM.

This is what it looks like on a 5 speed Boxster since that is what I have. Someone will help you with your 996.


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  • 7 months later...
  • 2 months later...
  • Admin
Is there a DIY for this or something that we can see to know where and what to look for?



Pretty easy - disconnect the electrical connector - unscrew old switch - screw in new switch - reconnect the electrical connector.


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  • Admin
Do you have a part number for this piece so I can get it from the dealer? Is this something that I can get to without having to remove any other parts underneath the car?


I will need the model year and exact model (C2, C4, C4S) and transmission (6 speed or Tip).
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