HP 2550 Error Lights in relation to fuser

Hi,

I think I have a fuser issue due to:

Primary Light pattern : The Attention light, Ready light, and Go light are all three on.

Secondary Light pattern : The Ready and Go lights are on.

But I can't tell if it's error 

Error 50015 or  Error 50010

Does it matter which it is? Will replacing the fuser solve this issue?

Thanks

Louis