C20 Checking Locking Signal Cables

Switch ignition off.
Connect central locking module 6-pin connector to front doors.
Lock driver's door using key.
Keep door key turned as far as it will go, at least 45°.




Connect an ohmmeter between position 31 and position LK on relay base G.
Ohmmeter should read approx 0 Ohms.




Unlock driver's door using key.
Keep door key turned as far as it will go, at least 45°.




Connect an ohmmeter between position 31 and position LK on relay base G.
Ohmmeter should read infinite resistance.

Repeat readings on passenger door.
If both readings are correct:
Open-circuit or short-circuit in signal lead (unlocking) between front door and central locking relay.
Correct fault or replace faulty signal lead between relay base position ULK and lead harness 6-pin connector position 2 in one or both front doors.
Replace central locking relay D/G and drive's door relay N.

If any reading is incorrect:
Open-circuit or short-circuit in signal lead (locking) between front door and central locking relay.
Correct fault or replace faulty signal lead between relay base position LK and lead harness 6-pin connector position 3 in one or both front doors.
Replace central locking relay D/G and driver's door relay N.