Heaters not working.

I'm about to buy a H-reg disco, but when I tested it, the guy said the heaters didn't work.
They heat up and go cold he said, but the blowers don't work.

I seem to remember someone telling me to be wary of buying one if the heaters don't work.
Is that only if the hot and clod doesn't work?
What could be stopping the blowers?

Thanks

The lack of 12v power supply

If the matrix gets warm then goes cold, it could indicate pressure in the cooling system from a head gasket failure, stopping fluid circulating properly. Not sure about the blowers though sorry, knackered motor or selector switch? If someone has had the dash out did they reconnect everything properly?

Just to clarify,

Your heaters work in both hot and cold mode (you can feel when they are warm/cold respectively) only they don't blow?

Or they blow but change from hot and cold intermittently on their own?

blowers did not work on my 96 tdi, the sliding switch was burnt out, managed to get to work ...sort of but it remains a bit iffy, if thats all it is wrong just budegt for a couple of hours taking the radio panel out etc and fitting a new one.

if the blower is working but not providing hot air then it could simply need the coolant topped up using the correct procedure, or the heater matrix could be blocked which might be a flush job or much worse (cos the whole dash has to come out to replace it ive read here) a new one required .......or lastly a major problem with the engine as prior post.

My blowers were not working when I got mine.... On a quick inspection it was just the large fuse under the bonnet had blown. They have worked fine since I replaced it.
Would be easy to check that on a test drive..... U never know u could be lucky and it be as simple as that!