Electric Tongue Jack Issue

Did you check the ground connection? A resistive connection on either pilarity could cause the voltage to drop too low during motor start.

Also, spray everything that moves with wd40 to lubricate it, or if you see corrosion try PB Blaster to get that loose. Then run the jack up and down all the way several times getting it started by hand cranking if needed. Basically youre trying to clear any corrision out of the jack and getting it lubricated.

If you still suspect weak connections get a multimeter, disconnect the battery, and use the ohmmeter function to see what the wire resistances are in both the plus and minus legs.

If none of that works you probably need to plan on buying a new electric jack. Or just use the manual jack and consider it a bit of arm exercise.

Remember -- a battery loses water by evaporation, not acid.  So don't add any acid- just water.  An d distilled water is best.  A 50 cc syringe or a turkey baster is a precise way to fill the battery, and your battery may have a Fill to Here mark.  Takes a lot more than you think it will if the liquid is just covering the plates.  the curve on the front of some pods makes filling the batteries a real exercise, but necessary .

Was able to do a deeper dive today and was somehow able to get it working properly - at least for now.  While I didn't use a volt meter I am fairly certain a resistive connection was the issue.  Here's what I tried and what eventually worked...  Visually inspected the wire from the battery to the jack - looked good.  I cleaned all the connections at the battery - still had the issue.  The 30amp fuse holder between the jack the battery had connections that looked corroded so I tried to clean but eventually removed it completely - spliced it with a quick connect and still had the issue.  Removed the top from the gear box and repacked with grease - still no joy  .  The only connection I could not check were the two wires going into the motor.  I was working to remove the motor but I would need to remove the gears to get to the mounting nuts - not up for that.   So as a last resort I expertly  jiggled the wires leading into the motor and now it's running like it used to.  I did more jiggling once it was running good and I can't get it to fail now.  I don't hold out much hope of that fix lasting one it get jiggled on the road but who knows.   I'm keeping the manual jack handle handy.  

Hate when that happens and you don't know the root cause. We had a similar thing happen after the first winter storage with the electric jack we installed on our 2017 179. We attacked it with WD40, checking connections, the whole enchilada. I manually cranked it and towed it home where, upon arrival it worked fine. My wife made a water repellant hood for the head of the jack to protect it from dust and the elements when the trailer is stored. Never had a problem after that. Not sure if that was the solution but we haven't had issues in the 2 years since then.