merc sprinter problem

[vorta]

i have a 2003 merc sprinter 2.2cdi camper van and have a strange problem. the dash, number plate and side marker lights only work with ignition on and engine stopped. if the engine is running i have no dash, number plate or side marker lights, all other lights work just fine.
any clues as to a soloution would be much appreciated.
many thanks in advance.

[TWR]

Have you just replaced a bulb in the system? has the bulb been the right one? other than that, there seems to be a short in the system quick fix, Auto Elec.

[vorta]

i've not replaced any bulbs but only had the van a few days so another wally could have replaced a bulb, but, they all work with engine off so i think the bulbs would be correct, not double contact in single contact holder or vice versa, probably have to take it to an auto spark.

[TWR]

It could take you a while to find the Source Vorta, best bet & quickest solution In my opinion Auto Elec.

[AlBags]

Has the alternator been replaced recently?
Check for wet/corroded relays in the engine and main housings.