I am a reasonably competent amatuer mechanic, so I like to fix things. I bought a 1999 T4 that had been converted to a camper a few years ago, it was in a reasonable condition, but needed some welding & a few minor repairs. From the start I noticed that you could only adjust the heater control at the valve under the bonnet. Somebody told me that the bracket breaks behind the control switch in the dashboard. So I purchased a new brass one, when I came to fit it, the existing one was ok, but the cable was not sitting in its clip, so the whole cable would move back & forwards instead of just the inner. Easy fix I thought and put it all back together. Checked that it was working ok & turned on the blower. It was ok for a couple of seconds, then there was a huge clunk & the fan started making a very loud rumbling noise. I diagnosed bearing problems in the fan motor & took the (newly fitted that morning) pollen filter out to access the motor from under the bonnet. Then I found the problem, in my haste to fit the new filter I had neglected to check inside it. The installation instructions had been inserted into the filter & the fan had sucked them in so that they were hard up against the inlet. A real rookie mistake that was easily rectified, without causing any damage, other than to my ego. Still picking bits of shredded instructions out of my beard as I write though.