Does anyone have the instructions to replace the FBH,

I suspect mine has drained the battery, I went out to the bin last night and i was sure i could hear a small fan running on the car which has not been usual recently, came out this morning to find a flat battery.

I have a spare heater on the shelf so i think its worth a try.

Very surprised no body picked up on this yet but you sure it's fbh and not the heater fan running slow because fsr packed up? Fuse 59 in front fuse box controls mine might be worth pulling it see if fan noise stops.

I actually thought I had the issue discussed in the topic below as every time I lock or unlock the car I heard a fan run for a while, I had assumed it had just stuck on and drained the battery, I have seen errors for the FBH in the gap tool but had never really investigated further.

https://www.fullfatrr.com/forum/topic58360.html?highlight=webasto