2016 Smart Car. Rear lights go out when main beam is on.

[John77]

We very rarely go out in the smart car at night and now we have found that the rear lights go out when main beam is on. This could have been happening for years as, as I said we do not use it at night. Nothing new has been done to the electrics lately. If it is something like an earth or you know what it is. Please say where on the car I will find what you say I should look at. Thank you.

 

[John77]

Well tried it again this morning and everything works ok. Maybe water is getting in somewhere. We have had a little rain lately.

 

[John77]

Lights went off again the other night, but fine again today. Checked alternator. 14.7v on normal running, 15.2v with lights full fan and radio on.
Battery is giving out 12.1v everything off, so I have ordered a new battery, as it is a little low.

 

[Blobcat]

I’d be checking for corroded Earth connections and connections

 

[norwoodboy]

Sounds very much like an Earth fault given it occurs when wet i would be checking all of the light seals back and front as water ingress is possible.

 

[John77]

Thank you. I have just noticed that THE TITLE IS WRONG. The lights DO NOT go out when main beam is put on. They go out when they please. I have just been out in the car tonight and the lights are fine. I am now wondering if the rain makes a difference. I will have to see what happen next time it rains.
I will check the seals.