Lost 12v power

[shov]

Okay folks I was getting everything ready to hook up my 12 Alpine 3600RS to leave tomorrow. I have the auto leveling hydraulic jacks, I opened the cover, turned it on and started to raise the rear jacks and the unit turned off. Then I noticed all of my 12v power is gone. The only thing that works was the clock on the microwave. I am no electrical genius so if someone could please help me look and or perform simple tests I sure would appreciate it. I was hooked up to shore power when it happened. And the batteries still had plenty of juice to start my generator. At a loss. Please help. Was planning on heading out of town tomorrow afternoon with my 5er. Thanks in advance

[outwest]

If it was working when you started to raise the rear jacks and quit while you were doing it, sounds to me like a blown fuse. Your 12V fuses are in the same panel as the 110V breakers.

[shov]

I did not pull all of them to look, however I didn't see one labeled for the leveling jacks. I guess that makes the most sense. I will pull them all and visually check them out

[shov]

Would one fuse kill my entire 12v system. I mean nothing 12v works

[kellydog98]

I have to believe that you also looked to see if any of your circut breakers had tripped. There are also fuses just past your batteries that should be checked. However, using shore power...make sure you didn't trip the breaker in your house also.

[shov]

The house breaker was good. And like I said the clock On The micro was on. I did check and actually turn off every circuit breaker and then back on to make sure. I did not check or see any fuses just past the batteries. I will look for those in the AM. Keep the ideas coming. And thank you

[outwest]

As already mentioned, there should be an inline fuse outside, up around the batteries and there might be some reverse polarity fuses in the fuse panel (that protect the entire 12V system). There should also be a fuse for the jacks in that panel.

Since you said that nothing 12V works, then it's a problem in the main 12V system somewhere. Worst case scenario is that your converter/charger is dead and the batteries became drained when running the jacks.

Do you have any 12V when you have 110V hooked up (or genny running)?

[wtxdxer]

If you don't have a volt meter, get one. It's difficult to trouble shoot electrical issues without one. Harbor Freight has very inexpensive volt meters but I've found those may have probes that the tips aren't long enough to reach the contacts in an AC outlet. They have nicer meters with better probes in the $20 range.

Once you have a volt meter you can check the battery and see if it's dead or not rather than rely on whether your generator starts or not as a test. I've never had an RV with a generator but I'm surprised the generator starter would use the same battery as the RV.

Also test the battery under load. It may show 12v with no load but if you try to run your jacks the the voltage may drop to 8v or something.

Locate your converter and check the output of it with the volt meter. Disconnect the battery when you check it or you may just be measuring the battery voltage. If you have no output from the converter check that you have 120v going to the converter. A handy device for checking that is a non-contact voltage tester. You just hold it next to an AC line and it will blink and beep if AC is present. Harbor Freight has those as well. I got mine from Home Depot.

If you have no output from your converter it's time for a new one. If you do have 12v out from the converter then start tracing the 12v line to the breaker panel and check fuses.

If the battery is dead you should still have 12v to the RV if the converter is working. If the converter isn't working the battery probably ran down and nothing that runs off of 12v will work.

The clock on the microwave is working because the microwave runs off of 120v AC. The TV should work too.

Alan

[shov]

Well this is why I love these forums, many of you have so much more experience than a lot of us, and I appreciate it!
So, this morning after reading all of the responses I got, decided to open the basement and start pulling wall panels (for the very first time) to reveal the guts of my electrical system. Let me just rant for a moment, what a mess of flexible duct work (it’s no wonder it seems it takes longer to heat or cool my 5er, there must be miles of wasted duct work in there), 12v/110 wire, and plumbing…
I swam through the mess to find the inverter, and on the back side I tested the fuses, low and behold one of the 40 amp fuses was toast. So I ran to Walmart (the only thing open that early in the morning) and of course they don’t have them. So, on my lunch break I will run to NAPA or across town to the RV dealer and stock up on a variety of fuses. I would sure hate to let a simple thing like a blown fuse to strand me if I am out in the middle of BFE.

So, again thank all of you for your responses, and I can only hope one day I am able to share something I have learned along the way to help someone else.

Sadly my area of expertise lies more with my Duramax tow vehicle, but I will continue to learn about my Alpine…

[Ken / Claudia]

I just read thru this and was going to say fuse. But, you found it. Now have several extras around. Advice I got from blowing them on last rv, factory guy said try not holding the power button moving them down for long time? I would move jacks alittle (2-3 inchs) release button, wait a second and start again. I never blew that fuse again unless I attempted to power them without a pause.

[shov]

OK, lets add one more perplexing dilema!

So I located the fuses (plus several spares and a complete variety for the future), got home and changed the blown fuse. The leveling jacks worked and I even took several pauses during, then all of a sudden lost power again. Checked the fuses at the converter again, this time they both blew. Changed both pressed on and the unit functioned flawlessly.

I will cycle through the operation several more times this weekend and report back. I can only assume that if this continues there is an intermitent short somewhere in the 12v system, correct?

Thanks for all the help and happy trailering

[JRTJH]

You probably have a motor on your jacks that is 'right at the limit" in power requirement. Let's say you have a 15 amp fuse and the motor pulls 14 amps until it warms up a little, then it pulls 15.2 or 15.3 amps and you blow the fuse.

Next time you go to NAPA, look in the electrical section and you'll find 15 amp automotive circuit breakers. They are about $3 or $4 each, but once you install them, they will open, then reset in a couple of seconds and that's just about enough time for your motor to cool down enough not to draw more than the CB/fuse is rated for. It's a "win-win" no more replacing for you and an "automatic" cool down for the motor.....

[shov]

Thanks for that bit of advice JRT JH! I will certainly instal those.

Update: I made it my location and set up without blowing a fuse!

Thanks again

[JRTJH]

That's great, enjoy the weekend !!!

[chuckster57]

FWIW, I'm starting to notice circuit breakers instead of fuses in the panel for slide circuits in the new units during my PDI's.

[shov]

That might be a very smart move on the side of the manufactures.

[rosede]

Originally Posted by shov

.....low and behold one of the 40 amp fuses was toast.

I was getting ready to post, "check the 40 amp fuses".

I had something very similar happen the first outing this summer. Last fall, I had the front cap repainted. When the body shop guy's replaced the battery, they hooked it up backwards, which caused the two 40 amp fuses to blow. I didn't know it until we were at the campground. We were plugged into the pedestal drawing plenty of AC, but everything still died, lights and AC (extremely hot day too).

After spending some time troubleshooting, I pulled one of the two 40 amp fuses and sure enough, it was blown. The label on the cover said that these fuses were to protect the camper from a reverse battery hookup.