I swapped the bulbs of the reverse and fog lights, fog still worked but not reverse so it's not that simple.
Even if the bulb was blown the parking sensors should still work.
From Rave:
"Reverse gear signal
The feed from fuse 25 in the passenger compartment fusebox is connected to the reverse
lamp switch (manual gearbox), or starter inhibitor/reverse light switch (automatic
transmission), by a GY wire. When reverse gear is selected, the switch closes and the feed
is connected to the ACE ECU, by a GN wire via header C0287 LHD/C0294 RHD, to provide
a reverse gear selected signal. The reverse gear selected signal is used by the ACE ECU
to set the system in a 'locked bars' condition when reversing."
"Reverse Gear
When reverse gear is selected, current from fuse 25 flows across the reverse lamp switch
(manual vehicles only) or the automatic transmission starter inhibitor/reverse lamp switch
(automatic vehicles only) to the PDC ECU on a GN wire. When the PDC ECU receives this
feed it registers that reverse gear has been selected and activates PDC.
PDC Sensors
The PDC ECU provides a feed to connector interface C2403/C2404 on a WG wire, and from
the connector interface to all four PDC sensors on W wires. The sensors are earthed on B
wires to connector interface C2404/C2403, and from the connector interface to the PDC
ECU on a BG wire.
The PDC sensors provide distance signals to the PDC ECU as follows:
The RH outer PDC sensor provides a signal to the ECU on an O wire.
The RH inner PDC sensor provides a signal to the ECU on a Y wire.
The LH inner PDC sensor provides a signal to the ECU on a U wire.
The LH outer PDC sensor provides a signal to the ECU on a G wire.
PDC Speaker
The PDC ECU powers the PDC speaker to give the driver an audible indication of the
distance to an obstacle. The PDC ECU provides the speaker a positive signal on a K wire
and a negative signal on an N wire.
Reverse Gear
When reverse gear is selected, current from fuse 25 flows across the reverse lamp switch
(manual vehicles only) or the automatic transmission starter inhibitor/reverse lamp switch
(automatic vehicles only) to the PDC ECU on a GN wire. When the PDC ECU receives this
feed it registers that reverse gear has been selected and activates PDC.
PDC Sensors
The PDC ECU provides a feed to connector interface C2403/C2404 on a WG wire, and from
the connector interface to all four PDC sensors on W wires. The sensors are earthed on B
wires to connector interface C2404/C2403, and from the connector interface to the PDC
ECU on a BG wire.
The PDC sensors provide distance signals to the PDC ECU as follows:
The RH outer PDC sensor provides a signal to the ECU on an O wire.
The RH inner PDC sensor provides a signal to the ECU on a Y wire.
The LH inner PDC sensor provides a signal to the ECU on a U wire.
The LH outer PDC sensor provides a signal to the ECU on a G wire.
PDC Speaker
The PDC ECU powers the PDC speaker to give the driver an audible indication of the
distance to an obstacle. The PDC ECU provides the speaker a positive signal on a K wire
and a negative signal on an N wire."
