12v refrigerator

[airlifter]

I have a 2003 Aliner with a Dometic 3way refigerator and I am having trouble running on 12 volts while traveling. When I bought the trailer it worked fine and at one point the refrig would be off when we reached our destination.

The voltage from the truck seems to ok. When I hook the truck up the voltage increases to about 14 volts. When I turn the refrigerator to DC the voltage drops to below 12 volts. I have had the same problem with two different trucks. I don't know what happened to cause this change. Any ideas on what to check?

I know that this is not information but I will try to get anymore information needed to help me trouble shoot.

All advice and comments appreciated, Pete

 

[Gary RV_Wizard]

You have high resistance somewhere between truck and the fridge. Could be too small a wire or a poor quality connections or corroded pins on the trailer connector.  The wiring isn't able to carry the amp load (th fridge on DC is a power hog!) so the voltage falls.

 

[frank1947]

Most helpful vid I've seen so far  )

https://www.youtube.com/watch?v=A7JboU8ZlE0

I hope you will find it useful also to troubleshoot your RV refrigerator.

 

[John From Detroit]

One thing to understand is that fridge on 12 v draws what about 250 Watts. that is 20 amps... As batteries age they loose capacity so when new it may be the battery had the reserve needed to make up for what the truck did not deliver but now they no longer do...  Just one theory.    On AC they draw around 350 (mine is 325 per Rachel) and even with a class a the alternator can't keep the batteries up.