Has anyone put a switch on a refrigerator defrost heater?

My Maytag has a Vacation Mode, which decreases the defrost cycles. I use this when we dry camp overnight.

MrWizard wrote:
i have not done anything to mine
but several other members have
according to the wiring diagram mine is a motorized timer, since we full time i just left it alone, i don't know how often it cycles

someone once posted 10 minutes every 10 hours
IDK, but i;ve never been much concerned about, and we dry camp 95 percent of the time
right now the fridge is empty and turned off, the RV is at the diesel shop

despite CPU technology
NOT everything has a CPU chip in it

Typical defrost cycle 10 minutes per 10 hrs of COMPRESSOR ON TIME is what I measured with my 10 cu ft fridge..

And yes, I HAVE rewired mine with a DPDT toggle switch to allow me to temporarily disable the defrost timer. The defrost heater on mine draws 250W.. I only have one pair of 6V GC batteries so I wanted to make sure that would be plenty of capacity for overnighting without shore power.

OP does need to be aware, SOME fridges use mechanical timers and some fridges use an electronic timer, mine uses a mechanical timer so I cannot guarantee if bypassing is possible with electronic timer.

You will have to study the wiring diagram (which should be glued to the back of the fridge) in order to determine how to connect a disable switch. I had to use a DPDT switch because of how the timer contacts work on mine, somehow the timer motor connected real oddly on mine, hence the extra pole on the switch.

I only disable while traveling, you MUST re-enable the timer at the earliest chance you get. Otherwise you will risk major ice buildup in the coils.. I would say you could go perhaps two to three days without the defrost enabled, after that the build up will make the compressor run longer and longer. You could go longer in dry climates but in high humidity areas like at the beach you will get build up very fast.

On edit.. Added in electrical diagram of my fridge, before and after mod..





Note, I had to add a jumper to the contacts of the DPDT switch..

i have not done anything to mine
but several other members have
according to the wiring diagram mine is a motorized timer, since we full time i just left it alone, i don't know how often it cycles

someone once posted 10 minutes every 10 hours
IDK, but i;ve never been much concerned about, and we dry camp 95 percent of the time
right now the fridge is empty and turned off, the RV is at the diesel shop

despite CPU technology
NOT everything has a CPU chip in it

It is like regeneration mode on modern diesels. You don't want it to click uphill.
I think the best way would be program the controlled to not go into defrost at those days. Household refrigerators have never been intended for it, but I would start with giving manufacturer a call and ask for engineer.
They might want to charge you for advise, or maybe hoping for more buyers will provide free help.
Doug is right that putting just a switch you will fool the computer with hard to predict consequences.

Defrost heaters do not run that much. In the OLD refer mechanical control's, the defrost heaters were on a mechanical timer. In the newer electronic control refers, I would bet it is on a temp sensor control instead of a timer, but you need to find out. The purpose of the defrost heaters is to remove the ice buildup from the evaporator/s. The ice restricts the air flow thru the evap fins and causes a loss of cooling in the refer. So, if you turn the Heaters OFF, you may cause a faster ice build up and that would cause the refer to run LONGER to maintain your temp. So, it would be a trade off on power consumption----either the defrost heater would run or the compressor would run longer due to the defrost heater not removing the ice build up. Doug