I have a 1985 Beneteau 345 with a Marine Air conditiong AC/heat (thats the brand) unit.  Its a single unit with digital thermostat for heat and a/c.  The unit pumps water from the lake for operation.

This is the original compressor with the capacitor replaced about 1.5 years ago.  The central heat/air unit works beautifully but now, I notice a very slight burning smell coming from the electric control box.  This is the box that interfaces with the boats thermostat.  Even with the smell the unit works perfectly.

Does the electric control box need replacing OR could it be a loose wire inside the box causing a issue with connectivity?  I've checked the wires on the outside and they appear to all be tight.

Thanks beforehand for any assistance you can provide.