15amp fuse for electric tongue jack

[Norm-n-Mary]

Hello All,
Our electric tongue jack keeps popping the 15amp in-line fuse. attached is a picture of a 30a & 15a circuit breaker on frame of trailer adjacent to battery house and elect. jack pole. Could these circuit breakers be our problem. How difficult would it be to find what's causing the 15a fuse to pop????? I'm not much into electrical know-how
Thanks in advance Norm

[ATCguy]

I'm not much of an electrical troubleshooter either, but maybe this will help get you started...

Does it pop your breaker (that's a breaker you're showing there... not a fuse) after the motor runs for a few seconds, or immediately upon pushing the button?

If immediately it could indicate a short-circuit somewhere... but if the motor runs a few a second or 2 beforehand, sounds as if the motor is requiring too much current... or the breaker itself is weak & needs replacing.

The breaker can normally be found at almost any auto parts store for a few bucks.

I'm sure the others will chime in later...

[Norm-n-Mary]

Hi ATC just to the right of the dual circuit breaker (outside of photo) is a 15amp in-line fuse which trips. The tripping of the fuse never happens when the tongue jack is engaged. It just trips when I'm not around. I have been lightly shocked while removing/installing swaybars. I guessing it maybe a grounding problem?????
Thanks Norm

[franktafl]

WOW, for you to have a HOT chassis is not good since it may do it when it's on shore power. Use a multimeter between the RV and the truck (when it's not plugged in) to see if there is anything there.

Even 12 volts can produce enough amperage to kill you...

[videoarizona]

This probably isn't your problem, but you should clean the breaker terminals. I see rust. Not good...
As a bad connection will cause more current to flow....

You mention getting a shock sometimes when you are touching your sway bars. Is the tow vehicle connected at the time? Is the 7 pin power cable connected at the time? The shock is most likely coming from either a ground potential between the trailer and vehicle electrical systems or you have a direct short to ground somewhere.

I would have the tow vehicle trailer electrical checked as well as the trailer.

[larrypride]

I’m an electrician. Have been for over 40 years. It would be very hard if not impossible to get shocked off your trailer if you aren’t connected to shore power or on generator or if you have an inverter. I did see a motorhome that had the neutral and ground connected and it was plugged into a receptacle that had the hot and neutral reversed causing the frame to be hot and a person was almost killed when they grabbed the door handle barefoot in the rain. Back to your original question. If it blows the fuse and the jacks are not being operated you have a short some where. Maybe a critter has eaten insulation off a wire some place. If the fuse blows during operation that’s a different problem. Let me know if you have any other ideas on when the fuse blows. Does it blow as soon as you put it together?

[kimbo@alum.mit.edu]

I would track down why your getting slightly shocked first. If your at home it could be a bad system grounding or an even more dangerous reverse polarity like Larry stated.

[persistent]

Originally Posted by Norm-n-Mary

Hello All,
Our electric tongue jack keeps popping the 15amp in-line fuse. attached is a picture of a 30a & 15a circuit breaker on frame of trailer adjacent to battery house and elect. jack pole. Could these circuit breakers be our problem. How difficult would it be to find what's causing the 15a fuse to pop????? I'm not much into electrical know-how
Thanks in advance Norm

Lots of good possibilities posted above.

The two devices you show in the photo are self resetting circuit breakers. They trip when over current through them is present. They reset themselves after cooling down briefly. They may be associated with charging from your tow vehicle or the electric breaking circuits. It is unlikely they are causing the 15 amp tongue jack fuse to blow.

The fuse, of course, blows when current exceeds capacity of the wire. Since the jack motor is not running when the fuse blows, the failure is before the switch that controls the jack or it could be inside the switch. Look for frayed insulation. Disconnect the switch on the hot side if you have access.

The shock or more likely sparks you get when hooking up the TT to the TV are a different issue. Assuming shore power is not connected at the time, it is likely a 12 volt power issue.

The TV has a battery and the TT has a battery. The 7 pin connector has a 12 volt positive pin in it so sparks can occur due to current flow between the batteries.

The other possibility is sparking when the two vehicles touch through the hitch. The 7 pin connector has a ground pin as well and it may spark when connected.

If the 7 pin ground is not working or is inadequate, the hitch parts may provide a ground connection and spark when connected.

If you touch the tow vehicles before a good ground is made, you may become part of the circuit. And feel a small shock.

It is unlikely the shock will kill you, however, it is possible. Most likely it will startle you. It may cause you to react suddenly and injure yourself.

Review the ground connections between the 7 pin cable on the TT to see that it is clean and working properly.

The ground on the TV may also need attention. The ground wire between the TV and 7 pin needs to be at least 10 gauge and should not show any corrosion on either end.

I wish you good luck and happy trails ahead.