12 Volt Problem

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
Riverdog

Riverdog

Well-known member
Joined
Mar 10, 2006
Posts
176
Location
Spokane Valley, WA
Any tech's out there that might provide some insight to this? I have a 2009 Komfort Trailblazer 285TSG. When plugged into shore power I have full power (lights, furnace, everything). When plugged into the tow vehicle (no shore power) I also have full power. However, as soon as I disconnect from the tow vehicle I lose all 12 volt power -- lights, furnace, everything.

Any ideas? I do have solid hookups on the batteries, both positive & negative. Does this sound like a bad trailer ground? Perhaps a problem in the wiring to the converter? Anyone encounter this before?
 
Do you have a "store" switch (turns off DC for storage)?  If you are not getting any 12 vdc and the batteries are good, it's fairly certain the batteries are not connected.  A common problem is this switch being in the wrong position.  I believe there are different ways RV mfgr's wire this.  Some (like mine) wire it so if the switch is in the off (store) position, nothing works on DC even if plugged in.  Others wire it so the converter can still supply 12 vdc when plugged in, but not when unplugged.  I have no idea where your switch would be, but mine is in the stairwell.  Now, if you are aware of the switch and have tried it, the problem might be the relay it controls.
 
If you know your batteries are fully charged and connections clean and tight, then the negative battery cable/Frame connection is the next place I would look assuming you only have one cable on the negative side and that's where it goes.
 
Yes I have the store  switch & tested it, bypassed it with same result. 

I will next test all grounds, plus trace the positive cable back to see if I missed a fuse.
 
Easiest way to test the battery ground cable is to use a jumper cable to bypass it.  Clip one end to the battery's negative terminal, clip the other to a good place on the trailer frame.  If things start working your problem is in the battery cable or it's connections.
 
In addition to the use/store switch, and the solenoid it remotely operates. There should be one or more circuit breakers of fuses..  These come in basically 3 flavors.

Circuit breaker, Thermal self-resetting, (This is what is on my motor home)

Circuit Breaker, Post type PUSH IN HARD to reset, (the wiring diagrams for the battery control system on my motor home shows TWO of these)

Fuses. You know how they work,  OFTEN these are 30 amp and often there are 2 of 'em.

It appears the converter, and the tow-vehicle charge lead are "House" side of this device.

How to trouble shoot two methods.

With no "External" power, take a test lamp and follow the leads,  Start with the clip on the battery negative and the point on the positive, LIGHT = GOOD, Dark = Bad.

now move the clip to a handy non-painted chassis part,  Same point spot.

Dark = bad negative, check the chassis end of the cable, LIGHT = Good.

Now follow the POSITIVE leads out,  all the time Light=-good dark =EUREKA I found the problem

If you are plugged in at a campground, Lift the NEGATIVE cable off the battery and this time start at the fuse block and work toward the battery.
 
PROBLEM SOLVED:  Thanks to SteveAE on another rv forum site.

Steve has the same type of trailer that I have & pointed out they have a fuse hidden up inside the underbelly of the trailer.  I did find it & it was an auto-reset fuse that had tripped.

Crazy place to put a fuse, but problem solved.
 
That's great news. I believe my Zeppelin has such a fuse mounted right next to the battery.

Question - "auto reset" seems to imply that you don't need to do anything to it.  Is that not the case?
 
I am fond of saying "They hide them".. This is true:

I used to own a '70's FORD LTD, and an ex-girlfriend an Olds of the same vintage. IN both cases the heater core needed replacement or repair.. The job involves (Per the manual) Draining the cooling system (per the job, clamp the hoses, forget draining) then you remove the hoses from the heater core, remove about a dozen screws, Lift the lid, lift the pad and core out, drop a new one in, replace pad (Felt) lid, screws and re-attach hoses, top off coolant.

That was then.. That is too simple.. The same job today:

Again, the books says to drain cooling system, but you can clamp it off.. Then you evacuate the air conditioning system, Disconnect and cap the lines to the evaporator at the firewall.  Dissassemble the passenger side of the dash. (Less it's a Renualt) slide the air conditioner evaporator out on it's rails and THEN you can lift out the heater core.

Again re-assembly is reverse.

On the Renault, the books says "Remove Steering Collumn" .

Why the change?

Well, back when it was simple, labor was like 20/hr, not it's 120/hr.
 
You must log in or register to reply here.

Latest posts

Members online

Total: 1,634 (members: 34, guests: 1,600)

Forum statistics

Threads
131,976
Posts
1,388,555
Members
137,726
Latest member
CampMike2270
Back
Top Bottom