Whirlpool F/F knocking off Trip’

I’ve been to look at a Whirlpool Fridge Freezer model number ART 871G which has been putting off tripswitch in house, it was connected along with Hotpoint dishwasher into fused spur, i tested both appliances found no fault, wired f/f onto plug, now customer says its going off now all the time, i took relay off compressor & checked motor, no short to earth & all looks fine, any ideas guys as to what may be causing this, appliance just over 14 months old!