When we camp we usually bring along a thermostat & remote sensor. While traveling, if we've turned the fridge off, the thermostats in the cab with us and the remote sensors in the fridge monitoring the temperature. While camped the thermostat goes inside the TT and the remote sensor outside in a shaded area.
Anyhow if you have a similar thermostat with a remote sensor you could place the sensor in the outside shower to keep an eye on it's health.
2007 Shamrock F19 hybrid - 2010 (22 nights), 2011 (24 nights), 2012 (11 nights)
2013 Surveyor Select 235RKS - 2012 (6 nights), 2013 (32 nights), 2014 (26 nights), 2015 (37 nights), 2016 (14 nights)