AC Unit with heat strip

[kinnycut]

I have had this A/C unit several years now and it has worked great. Recently I have a fuse in it that has been blowing frequently, but it seems related to when I use the heat because I cannot recall the fuse blowing when using the AC. I am thinking perhaps there is a issue with the heat strip now since it seems to only blow when it is real cold and the heat unit is turning off and on a lot. Does anyone out there have and suggestions or opinions on this? I was thinking thermostat at first, but if so why wouldn't not blow when the AC is running? Second, the fuse only blows out with the heat strip when it starts going off and on a lot. Thanks!

[jumptrout]

Brand and model number of the unit?
How many fuses and what size?

Amperage of circuit breaker supplying the unit?

POst wiring diagram if available.

[Bobice]

When the heater warms it expands. When worn it touches the cabinet and shorts blowing fuse.

That's why it doesn't happen in cooling mode.