Hello,
I've had the same problem with my Hoover dryer. The fault was the thermal fuse (or "Microtemp") in the heater at the back of the machine. When this 'blows', often for no obvious reason, the power to the heating element is cut off and the 'Filter Care' light glows continuously.
Take off the silver metal back plate (lots of Philips screws around the periphery), and then you'll see the heater. This is held in place by 2 screws at the top, and its lower edge has 2 prongs which hook into slots in the machine's rear. Note the wire mesh between it and the machine's rear - make sure it goes back in the same place! The thermal fuse is a silver, bullet-shaped device about 5mm in diameter and 20mm long, with wires coming out of each end.
As "E.Lambert" says, the official Hoover way of doing things is to replace the whole heater assembly. But as the defective part only costs about 50p, this seems a shame. It's possible to replace the fuse by itself, but it's a FIDDLY job, not really one for most DIYers. The trouble is that the fuses are wire-ended, and are attached to the heater's wires by crimps (little metal tubes into which the wires are poked, which are then squished flat in a special tool to hold the wires firmly). Even if you had the right tool and crimps, access is so limited that you probably couldn't use them.
A replacement can be SOLDERED in, but you have to carefully clean and tin the black wires from the heater first, and then keep the body of the fuse cool - using aerosol freezer spray - while you solder the wires onto it. If you overheat the fuse (easy to do, as the soldeting iron will be at about 300 degC and the fuse blows at 152 degC), the problem will persist.
NEVER SHORT OUT THE FUSE, EVEN AS A TEMPORARY MEASURE, OR YOUR MACHINE COULD EASILY CATCH FIRE.
I replaced mine several months ago, and it's been fine since. Having said that, this is one of the most shoddily-built bits of equipment I've ever seen, and I expected a lot better from a big name like Hoover, especially as it cost £270.
The other fault I had was a BIG bang and lots of acrid smoke. Sounds terminal, but it was only the mains suppressor, which stops interference from the machine getting into the mains and causing problems with your radios, computer, etc. Best to replace it with an original Hoover part, of course. But if you do what I did and bypass it by replacing it with a 3-way connector block, you MUST add a short yellow/green wire from the earth terminal of the connector block to the machine's casing, using a crimped-on ring terminal and shakeproof nut/bolt to make the connection to the metalwork. If you don't, the machine won't be earthed and you could get a severe shock (or worse).
Good luck.
Nick the Dentist
September 2004