Freezer problem:- defrost heater stuck on, why might this be?

It's a Hotpoint 8591a, the defrost heater is stuck on 24/7 and the fan isn't blowing so could it be defrost timer/thermostat, fan or drain problem?
Any advice appreciated, cheers.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The defrost timer may need a bit of adjustment. The defrost timer should have either a thumb wheel or a slot for a screwdriver on the front of it, and turning it slowly anti-clockwise until the compressor starts, maybe all that is needed. You can identify the timer by the shape of it. Most are a rectangular shape with one corner cut off ( a bit like this :
http://users.ev1.net/~oschmidt/deftimer.gif ) and they will have at least four connected wires along one edge.
If you give the cam a turn and the compressor starts, then in a day or two it fails again, this means that the little motor in the timer has failed or is failing and the unit will need replaced.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.