How hot is it down there?, these fridges take about 30 degrees out of the general temperature the fridge is in, ie if it's in the awning and that's at 45C, then the fridge will only get down to 15C.
If that might be the reason? then a cheap fan blowing over the lower part of the fridge can aid cooling the back of the fridge and get the beer a lot cooler.
note, if it's running on gas you will need to safely protect the flame from the affects of the fan.
JTQ, I've fixed countless fridges simply by turning over and listening for the last drop of liquid to drop and then turning back, what I want to hear is 10 seconds of dripping and at best 13 or 14, hence I say 15 seconds. All this does is remix the fluids which may have seperated into layers
What I found is it won't work or at least work well below 10 seconds, ie, there is a mechanical blockage, if I hear more I'll expect it to work once switched back on.
Once when my workshop was very hot I struggled to get what I expected to work, to work, what I then found was it's the very bottom pipework that overheats and it's this then that needs most cooling.
Also it works better if the back is fairly closely boxed in to create a chimney effect to get best use of the movement of air from the fan over the whole back of the fridge, that also applies to fixed fridges in vans.
Again if running on gas materials used must be carefully choosen