Reverse light switch on Citroen C4 1.6 HDI EGS

[Pissacake]

Hello!
Are there anyone kind enough to tell me where the reverse light switch is located on a Citroen C4 1.6 hdi with EGS gearbox?

Many thanks!

[GiveMeABreak]

I think reverse gear authorisation is controlled by the piloted gearbox ECU on these depending on engine speed / speed of vehicle, gear selection controls etc., so that the hydraulic actuators only allow reverse gear to be initiated when certain conditions have been met.

[Pissacake]

Sorry, I meant the reverse light switch

[GiveMeABreak]

I'm still not understanding you - what switch? The rear reversing lights are enabled electronically when reverse gear is selected.

[Hell Razor5543]

I think Pissacake is asking "Where is the switch that manages the reversing light?". I know that, on normal gearboxes, there is a switch that is activated when reverse gear is selected. I would have assumed that an EGS gearbox is the same, but I believe that GiveMeABreak is saying ( as the gearbox is managed by the electronics and not by a mechanical linkage) there is no actual reversing light switch, and the reversing light are controlled by the gearbox ECU.

[GiveMeABreak]

As you are not physically changing gears yourself, the gear and clutch engagement is managed electronically. Example being that reverse gear isn't allowed unless the vehicle has come to a halt and you have your foot on the brake pedal. So it is managed differently on the piloted system as far as I can see, so there may not be a physical 'switch'.

[Hell Razor5543]

I have a simple question that may be relevant to the original question. Is the EGS gearbox a manual gearbox with the additional equipment to allow an ECU to change gear? If it is, then it is conceivable that there is an actual reversing light switch still in place, controlling the reversing lights.

[GiveMeABreak]

There would no point in that at all - if the piloted gearbox ECU electronics rely on both vehicle and engine speed to meet the required conditions, and also require the brake pedal to be pushed before authorising reverse gear to be enabled and the actuators then carrying out the command, there would be no point in having a physical switch used for a mechanical gearbox - that would be totally redundant. All the checks and balances are done by the electronics, so putting on the reversing lights would be a simple command, There is no physical connection from the electronic gearbox selector to the the gears by the driver - only an electronic control and the steering wheel flappy paddles according to model and type of system.

[GiveMeABreak]

These are the main components on the early C4s with Piloted Manual Gearbox:

Gear control at the steering wheel
Gear selector
Gear engagement sensor
Gear selection sensor
Electric pump unit
Clutch sensor
Controlled manual gearbox input speed sensor
Piloted manual gearbox ECU
Controlled manual gearbox automatic mode switch
Brake twin function switch

[Pissacake]

The problem I’m trying to solve is a faulty reverse light. The bulb is fine so I was assuming the error might be a reverse light switch but I’m having trouble finding it on the gearbox. As The EGS gearbox is a manual but electronic assisted gear box I thought there would be a switch just as on a manual gearbox. If there isnt any switch, are there a fuse or relay where could the issue be?

[GiveMeABreak]

Pop your VIN up and I'll have a look at the circuit

[terppa23]

I have similar problem with my 2007 c4 hdi egs. Any advice how to fix this?