Morning. First post in this section so forgive me if its all old hat! I have a Westfalia James Cook ( fantastic van) with a Heki 4 with a Heki rain sensor that closes the vent if it detects moisture. V useful but it can be over sensitive and close the roof when eg boiling pasta and at night when just dew. Has been a pain these hot nights when want to keep the vent open all night. So picked up from the James Cook German forum a straightforward mod for an override switch. If anyone thinks that might be useful to them , then say so and Iwill post full instructions and where I got the cheap bits to do it. Cheers.