A 2006 Renault Laguna came into the workshop with the electric handbrake not operating. After checking for fault codes, but not being able to communicate with the ecu, i had to carry-out some ‘old-fashioned’ tests.
After consulting the wiring diagram and checking the wiring to the motor (which is a combined motor and ecu above the rear axle), i found the main feed to power the motor was missing. With the help of the wiring diagram, i was able to trace the wiring to a connector underneath the rear seats. On closer inspection i found the wiring to the motor chafed through!
Once the wiring was soldered together, i tested the system and found it to working correctly, without any expensive additional parts replaced unnecessarily.