Had a new battery and altenator on my van a week ago.

Also had a second hand fuel cut off switch put in as the old one failed and the van wouldnt start.

Now after a week or so its really lazy starting and the battery is going flat.

At first i thought id put the leads on the altenator wrong but on long runs it charges the battery and the battery light dosnt come on so i don't think theres a fault with the altenator.

I think it could be the fuel cut of switch draining the battery as somtimes you can hear a faint buzz coming from it.

Any ideas? (Need van for work so its urgent)