Tongue Jack Blowing Fuses

[pdlarson]

Not sure if this belongs in Travel Trailers or Tech but here goes: My electric tongue jack keeps blowing 30 amp fuses. I don't recall this happening for the first year or two I had it but suddenly earlier this year I started having trouble. There is a manual override but it is very difficult to crank. I have a supply of fuses that has helped me out of a jam but I'd be curious to know why this is happening in the first place. I don't see anywhere where it says what size fuse to use, 30A is what it came with new so that is what I have been using. I know that in general the recommendation is to not insert a higher rated fuse and to inspect everything because fuses blowing could be a sign of other trouble. The problem is that I can't seem to find anything wrong. This typically happens if the jack is over-extended in either direction (not on purpose or for a long time but you never know when it will stop until it stops) or when just starting to lift the tongue. Any ideas?

Thanks!

[wa8yxm]

I am going to second lubrication suggestion .. WHY "Because it is very hard to crank" suggests lubrication is needed.

[Ivylog]

Unfortunately this is very common for several reasons. The wire size is barely big enough so you get too much voltage drop once the friction increases from using he jack. At the price of fuse's, I'd run bigger wire and use a 40amp fuse plus lube it.

[RJsfishin]

Fuses blow because the amperage going thru it is more than the fuse is rated for. (Duh?) Like we dint know that 🙂
Ok, why is the amperage too hi ?
Besides all the reasons below, remember, when voltage goes down, amperage goes up. So, check the voltage at the jack while operating the jack. It may just be a problem of low voltage, either from a bad connection, or a battery that is not what it used to be. Load test the battery !

[Duck]

We do not have a TT but a fifth wheel. I know that if I over extend the front landing gear jack it will blow a fuse. You might need to use some wood under the jack to keep from over extending the jack.
Don

[old_guy]

are you reversing direction before the jack quits traveling up or down, that will blow a fuse also.

[BTPO1]

I do not a have a TT but I do know that fuses blow because they got to hot and melted. The reason they melted might be as stated earlier that your jack needs to be lubricated, non-lubrication makes it work harder. You also mentioned that it does it at either end of travel which to be means that it is binding and causing a higher current draw. If possible stop it before reaching the upper or lower limits. You are correct when you say that you should not replace a fuse with a higher rated fuse, you may end up with a mass of melted wiring. JMO

[camperpaul]

Try lubricating the jack.

Your owner's manual will tell you which lubricant to use and the locations of the lube points.