There are two completely different symptoms that many people confusingly report using the same language. So it’s important to make sure you are looking at the right article. If when you say the washing machine is not spinning you mean (as many do) that the drum is not revolving on any part of the cycle then you need a different article – washing machine drum not turning.
If you are investigating a fault where the drum is turning normally on wash and rinses but it’s just not doing the fast spinning at the end then continue with this article.
Not Spinning Because it can’t Drain the Water Properly
The first thing to check is has it pumped out the water properly?
A washing machine will not spin if it hasn't pumped out the water, either at all, or just not fully within the set time allowed due to a partial obstruction. However, don't start suspecting a pump problem unless it's obvious that the washing machine hasn't drained the water out, and has left quite a lot inside. Don’t mix up the amount of water that will naturally be left inside from laundry if the washer hasn’t spun with the amount left if it’s failed to pump it away.
Try it on a spin cycle again. Can you hear the pump running? Can you hear water going down the drain or into the sink u-bend? If you suspect a pumping out fault follow this article – Washing machine won't empty water
Load Out Of Balance
If the water seems to have been pumped out but it just won’t do the spin then check the wash load. Modern washing machines have built in out of balance protection and will refuse to spin out of balanced loads to protect against serious damage.
The worst loads for this problem are single items which are heavy when wet, or small loads, particularly if they have a single heavy item amongst them.
Therefore there is always a possibility there isn’t an actual fault. A quick check would be to see if the washer spins with no load in, or with a totally different (fuller more balanced) load. If it does, check this article carefully to understand this problem – Washing machine wont spin just one item or very small loads
Not spinning due to pressure system fault
Maybe it just thinks it isn’t draining water because it’s not getting the “water has now gone” signal.
The washing machine needs a signal from the pressure switch to tell it when the water has gone. A faulty pressure switch (or more commonly a blockage in the pressure bottle) can stop the signal being sent. So the washer refuses to spin. It will do the slow turning at the beginning where it distributes the laundry, pump out the water, but then after a few minutes just stop.
To understand how a washing machine controls water levels and knows when the water has drained away see this article – How washing machines control water levels (there are links in the article to common pressure system faults and DIY repair help).
Not spinning because motor is faulty
It is possible for a worn motor (or more commonly worn carbon brushes) to cause it to struggle to get up to spin speed but manage to turn the drum on wash and rinse. Normally such a fault would also cause problems on wash and rinse so it’s not too likely. However, if when it gets to the spin cycle the motor appears to attempt a spin but makes a strange grating or crackling noise and sounds half-hearted (maybe fluctuates up and down in speed) there could be a fault on the motor.
If the motor is sparking a lot you can suspect worn carbon brushes. Note that many washing machines don’t have carbon brushes any more. How can you tell? Open the door and spin the drum by hand. If it is virtually silent it’s probably a brush-less motor. If it makes a whiny ratchety sound that’s probably the brushes running over the segments in the armature.
If a drive belt is worn it could be slipping. It’s not so common these days but should be easily observed with the back panel off if this is what is happening.
If the water is being pumped out OK, and it doesn't appear to be an out of balanced load, then proper fault finding is necessary. This really needs the use of a continuity test meter and proper knowledge of washing machine repairs.
If it isn’t caused by any of the faults described above it only really leaves faults on the main PCB (or module), connection faults, more complex motor faults etc. It would be unwise to start buying parts speculatively, which could easily prove an expensive mistake.
Don’t get carried away
DIY Repairs SAFETY
Don’t be complacent – or over confident
Over the years, even experienced appliance repairmen have been seriously injured or killed. Don’t mess with electrical appliances unless competent to do so.