I have a weird issue with heating and aircon.
Heating and a/c were working fine but had the humming noise when ignition off and battery drain after 2/3 days.
Much reading here and youtubing suggested a dodgy final stage resistor. It was summertime but not too hot so just pulled fuse which solved the battery drain but obviously had no heating.
Now it is wet and cold I ordered new FSR, britpart one, and swapped it this morning.
All seemed well as now humming, and turned on blowers and everything appeared to be working.
Problem is now I can't turn them off! Even when ignition shut off and fuse removed. Had to disconnect the battery.
But even with no fuse in the blowers start again as soon as battery is reconnected.
Does anybody have any ideas what's going on?!

Check the FSR is properly seated in its "hole" .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

I did wonder if that might be an issue as when I removed all panels etc again it felt like it might not be correctly seated.

But given that the seating and removal is a faff, I then fitted the old one again without seating it and the permanent blower on problem was solved, so I made sure the heating and everything was turned off, then removed fuses. And then I put the new one back on and as soon as the connection was made blowers kicked in full pelt. This didn't happen when I originally fitted the new FSR.

Is it a known issue that it won't work correctly without being seated in that hole?

my gut is telling me it is not because of incorrect seating, but if that is a known issue then I'll ignore my gut and seat it correctly and see what happens.

It won't work properly otherwise. A bit like not having the plug in the bath properly. .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

ok thanks, good to know. Will refit the new one and double check the seating, and hopefully that will fix the issue.

New one is back in, and definitely seated correctly now, but unfortunately problem still remains.
I'm a bit stumped. The only thing I can think of is to order another FSR, just in case I got unlucky and the new one is faulty.

I'm, having similar issues with one of ours. Everything looks as if it's working but the heater fans don't come on. The rear fan works fine. So far as I am aware this is classic FSR failure, so I happened to have a spare in the garage. All changed and fitted correctly (spring clip snaps in to place when it's seated), still doesn't work. It could a faulty replacement FSR, it has sat in my garage for some 10 years, so I've ordered another (Febi Bilstein) from Advanced Factors, we'll see if that fixes it. Drives:
2010 FFRR TdV8 Vogue - Stornoway Grey
2010 FFRR TdV8 Vogue SE - Zermatt Silver
1998 BMW E36 M3 GTII