Front Lifting Jacks Keep Blowing Fuse

[BB_TX]

Is your battery in good condition and fully charged? Low voltage to a motor will cause that motor to pull more amps than it will at full design voltage. With low voltage your jack’s motor could be pulling higher current than normal and blowing the fuse.

Unlike a resistive load (light bulb for example) where low voltage results in lower current flow, for an inductive load (motor for example) lower voltage results in increased current flow.

[Igoo65]

Yes my batteries are fully charged. They were on the battery charger the day before.

[edb]

I own a 2007 Montana 5th wheel and have the same problem. I found if you do not extend the leg too far out the fuse will not blow. If you google it you will find that the older Montana's were notorious for this. Design flaw. Is there a fix? maybe since I see lots of people responding but my fix works just fine. Don't extend the leg past a certain point and voila!!! no problem. When I figured out the sweet spot I marked it with red nail polish. I haven't blown a fuse since then.

[Dean A Van Peursem]

Originally Posted by Igoo65

I have a new to me 2007 Montana 3000RK and everytime I lift the front I blow the fuse that is going to the relays that are attached to the batteries. Do I have bad relays or could there be another problem? I attached a picture of the 2 relays. The fuse is attached to one of the orange wires. Sorry the picture is upside down.
Thanks for the help!


Igoo65

We had a 2006 Thor/Keystone/Montana 3400RL that had the same problem. However, replacing the original fuse with the same sized fuse solved the problem and it never ever reoccurred. Is it possible that you may have some binding on the lift jacks? Or is it possible the original fuse was undersized? If the jacks are of the screw or gear type, it might help to lubricate the screws or gears. Another test would be to use an external jack to raise the front end up higher than normal and then run the two front jacks up and down to see if there is any binding when they unloaded. A low battery, dirty battery connections or loose connections could cause the same problem. Check your voltage at the motor that drives the jacks under load and see if it is significantly lower than the battery voltage. If so you have a bad connection somewhere. At a lower voltage the motor draws more current trying to do the same job. That may be causing your fuse to blow.

[spantz]

Had the same issue. I ended up replacing the landing legs ($200) myself and now no more issues. Look on amazon.

[Dean A Van Peursem]

He doesn't have the resetting type fuse if it is connected to the relays as he has described.

[Dean A Van Peursem]

Having the batteries on the charger the previous day does not necessarily mean they remained or even attained a full charge. If you have two 12V batteries in parallel one bad battery can pull down a good one. If you have two 6V batteries in Series then one or both of the 6V batteries may not be holding full charge. Full charge should be well over 12 V or 6V unloaded. Checking what the voltage does, at the battery, under load would be my first check. If any battery drops below 12V in parallel or 6V in series under load you have a bad battery.

[grampachet]

Changing directions while using jacks without letting them stop completely will also blow the original fuse. Did it a number of times, then installed the 30 amp breaker. Now after 10 years the breaker started to trip even after lubricating the jacks. Changed the 30 amp to 50. The 50 came from the slide circuit which was replaced with an 80.
That’s my story, everything is working now.

[Dean A Van Peursem]

There is some really bad info being provided here. This is a problem with the front landing gear. Not the slides blowing a momentary breaker. That is totally different issue. For that Montana recommended putting a parallel breaker of equal value to keep from that momentary fuse from breaking. Totally unrelated to this. The original past stated that he was blowing the in-line fuse. Now he is stating that after replacing that fuse the auto reset fuse if blowing. On my RV there is only one inline fuse between the battery and the motor that drives the front legs. I'm very confused

[Dean A Van Peursem]

Originally Posted by Igoo65

I first blew the inline fuse when I initially lifted the legs. I replaced the fuse and then the breaker went. The legs seam to go up and down smoothly. I don’t see any binding.
Igoo65

Which Breaker?

[John Shasky]

i had a 2008 with the same problem. Turns out the legs were poorly lubed from the factory. They finally wore out and blew the fuse when lifting. I had to replace both landing gears at my own cost. They were Lippert landers. I made sure the new ones were greased.
I just happen to have a brand new left side one IT was damaged i shipment and I replaced the drive shaft that attached to the electric motor. I paid a little over $300 for it. If we could hookup somehow, you can have it. I am in Southern Arizona in Tubac, 40 miles South of Tucson. JOHN

[Ernrays]

We also have a 2007 Montana, just a size down from yours. We too were having trouble when lifting with the landing gear. We'd blow several 30 amp fuses each time we used it. There are several potential causes when this happens, and you have addressed several of them. There is another potential issue and when we solved it with our 5 wheel, we stopped having problems with the landing gear.

Our 2007 had been in Arizona for most of its "life." The lubrication of the screw inside of the landing gear had "dried" out. We thought it was a bad motor, but went on line and saw how several other RV owners had serviced their landing gears. We followed their suggestion (applying grease using the inside of hot water pipe insulation). Our problem stopped immediately. The job wasn't hard, wasn't time consuming, but was very effective (and cheap I might add). If that is the core problem in your case, you'll keep blowing the breaker after the service has been completed. If it is the cause of your problem and you do the maintenance, you'll see an immediate improvement.

Good luck somehow seems to be connected with good maintenance on these older rigs. We hope you enjoy your Montana as much as we enjoy ours.

[Razahoryin]

I have a 2007 3000RK
It had the same problem
It’s not the resettable fuse

The in line 30 amp fuse that keeps blowing
It was a poor or weak set up
With a motor gear box and cross over bar
Thinking mine was worn or gear box or a leg going bad/bent
Could never solve issue

Ultimately I had to replace the landing gear
It’s really simple..to do
I selected the ultra fab heaver capability landing gear set..
Has independent electric motors on each leg
Problem solved.. I still have the rig with no further landing gear issues

[Igoo65]

Thank you everybody for all the information it has helped tremendously! This weekend I was able to look at the landing gear and what I found out was that it was almost bone dry. I went and poured some 90 weight gear oil down into the screw drive plus I packed the bezel gear with high temperature grease. Unfortunately my truck is in the transmission shop having the transmission rebuilt, so I will not be able to hook up the trailer and lift the landing gear until next week. When I’m able to lift the landing gear I will lubricate the screw drive using the insulation and grease method. I will report back after I am able to fully lube the landing gear to let you know what happened! Once again thank you to everybody with all their suggestions and helpful information!
Igoo65

[Nib]

Originally Posted by Igoo65

Here is a better picture of my wiring. I pulled the batteries out of it for storage.

Hi...glad you posted this, as I am just taking possession of a new-to-me 2008 3000RK. It's 200 miles away right now but spring and summer aren't far away! Would you happen to have any more pics of your hydraulic pump area and electric motor for the front landing legs? Just trying to learn the system a bit before I actually get to my rig!

Cheers, and happy camping in 2021,
Richard in Canada

[Igoo65]

Originally Posted by Nib

Hi...glad you posted this, as I am just taking possession of a new-to-me 2008 3000RK. It's 200 miles away right now but spring and summer aren't far away! Would you happen to have any more pics of your hydraulic pump area and electric motor for the front landing legs? Just trying to learn the system a bit before I actually get to my rig!

Cheers, and happy camping in 2021,
Richard in Canada

I will try to get some pictures today and post them. I di finally replaced my lifting motor with a heavy duty unit. I haven't had a problem since.
Igoo65

[twindman]

I had a leg get bent because I parked on a slope and didn't have the wheels blocked good. After that when one leg was halfway down, it would start to bind. I installed a new leg and all was okay after that.