Fault code 1830: Diagnosis/troubleshooting

NOTE: Visual inspection: In the next troubleshooting section, please check first that the affected pins on the rear convenience system control unit plug connection are neither damaged nor corroded. The wiring and plugs of the affected components must also be checked for external damage and proper contact. Repair damaged or corroded pins if possible, otherwise replace affected pins. Repair or replace damaged wires.

NOTE: Sporadic faults: In the event of faults that occur sporadically, the wiring positions that are linked to moving parts on and in the vehicle must be checked for each system. Various statuses that can cause faults must be simulated with the help of the wiring diagram.

NOTE: Battery voltage: A battery voltage of between 11.4 and 14.5 V is required for the following troubleshooting procedure. This must be checked and provided, if necessary. On the vehicle electrical system, the voltage to the fuse (input side) must be guaranteed.

NOTE: In the left tail light unit area of the wiring harness there is a plug connector (rear cross-over) that must be included in the checks.

WORK INSTRUCTION CHART

Work instruction			Display OK	If not OK
1	Visual inspection	Switch rear fog lights on	Left rear fog light and right rear fog light do not come on Go to step 2
2	Check bulbs for fog lights		Go to step 3	Check bulb for correct wattage and operating voltage (12 V/21W) and replace if necessary → End
3	Check line to left rear fog light for open circuit	Switch off ignition Pull plug B off rear convenience system control unit Pull plug off left tail light unit Pull plug off right tail light unit Measure resistance between pin 10 of control unit plug B and pin 6 of left tail light plug	< 5 Ω Go to step 4	Check, and repair if necessary, pin 3 of the rear crossover plug connector in the left tail light unit area. Repair line → End
4	Check line to right rear fog light for open circuit	Measure resistance between pin 10 of control unit plug B and pin 6 of right tail light plug	< 5 Ω Go to step 5	Repair line → End
5	Check line to left rear fog light and right rear fog light for short circuit to ground	Measure resistance between rear control unit plug B, pin 10 and ground	∞ Ω Go to step 6	Check, and repair if necessary, pin 3 of the rear crossover plug connector in the left tail light unit area. Repair line → End
6	Check ground supply of left rear fog light	Measure resistance between left tail light unit plug, pin 2 and ground	< 5 Ω Go to step 6	Repair line. Check ground pin 41 and repair if necessary → End
6	Check ground supply of right rear fog light	Measure resistance between right tail light unit plug, pin 2 and ground	< 5 Ω Go to step 7	Repair line. Check ground pin 40 and repair if necessary → End
7	Check left tail light unit	Measure resistance between pin 6 and associated contact springs in bulb holder Measure resistance between pin 2 and associated contact springs in bulb holder	< 5 Ω Go to step 8	Repair or replace left tail light unit as necessary → End
8	Check right tail light unit	Measure resistance between pin 6 and associated contact springs in bulb holder Measure resistance between pin 2 and associated contact springs in bulb holder	< 5 Ω Go to step 9	Repair or replace right tail light unit as necessary → End
9	Rear convenience system control unit faulty		→ End