2004 coach elec gone bad. Fuses? Other?

HawksEye

Member
Hi y'all-
I bought a 2003 sprinter- 2004 LTV FreeSpirit conversion this spring with the understanding the coach batteries needed replacing. They did just fine until 2 weeks ago, when the coach electrical battery monitor showed them losing charge then they quit. The night they quit, my LPG detector also went on the fritz showing it needed replacing.

I replaced the 2 6V Trojan-125 batteries with NAPA ordered (almost) equivalents, and they do not register on the monitor panel- coach systems are acting like there are no batteries. Manual says coach fuses are "on the front of the kitchen cabinet" but I cannot find them anywhere. I've seen the fuses under the driver's seat, but I have yet to find any coach fuse box. <==> WHERE is IT?

I will be checking fuses, when I find them, and current around the batteries. I have limited knowledge, but I have a multimeter :)

Any suggestions will be greatly appreciated!
 
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hayduke

2005/2006 leisure travel
It is across the street from the kitchen near the floor under a black door with a thumb screw
 

HawksEye

Member
well, no thumb screw, but I can fix that! [edit- different kind of thumb screw than I was expecting]
Thanks! Too bad my owner's manual wasn't right...

[EDIT]
So, new MultiMeter put to use:
Each battery has >6V coming out, but at the coach fuse box I do not get any current reading from the battery leads.
Flipped each circuit breaker. Tested each fuse.
No sign of rodent sabottage in the wires from the batteries on the bottom of the van.
My only concern with the battery replacement is that one of the (negative) terminal connectors was very thin and tiny...

Don't know if this is a clue, but even with the engine running, I get no coach power.
 
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tinman

Well-known member
If your fuses are all OK, check the latching relay that sends power from the house battery to the 12v. bus. On mine it's located in the upper forward corner of the compartment under the refrigerator, where the hot water tank and bypass valves are found. You have to remove the wooden cover behind the door. the switch is easiest to look at with a flashlight and mirror. it should make a fairly loud click when the switch on the master indicator panel is cycled, but the click doesn't guarantee that the relay is making good contact.

Andy
 

HawksEye

Member
If your fuses are all OK, check the latching relay...... it should make a fairly loud click when the switch on the master indicator panel is cycled.....Andy
so is this my latching relay? has 2 5A fuses on it, big power cords coming in/out on top and bottom.
What do you mean "check the latching relay". How do I check it?

The master indicator panel has no power. None of the switches light up, no indicators, and my propane is off. I can't even use my propane stove for breakfast :-(
 

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tinman

Well-known member
That is it. You should have battery power to one of the big leads, and when you cycle the spring loaded switch on the master panel, you should hear the relay click as it latches closed ( if it was open before). Both big leads should be hot when the relay is closed. if it's not making any noise, check those fuses. If it is clicking, and the relay isn't closing, it's likely bad. If you plug in to shore power, btw, your master panel should have power irrespective of the relay state.

Andy
 

HawksEye

Member
So I plug into shore power and my main panel switches do not have power. :-( No coach lights. The lights on the microwave display do turn on.

What activates behind the breaker box when plugged into shore power? I usually hear some little electrical noise (a converter fan?), but tonight, the noise sounds sick and there is a smell. Sick meaning it isn't a steady humm, but a faint rooo-rooo-rooo-rooo and I get readings that bounce from 1-5V (at the battery input at the breaker box) in rhythm with the noise.
 
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tinman

Well-known member
Unfortunately LTV doesn't give much of an electrical schematic, and i haven't had to chase enough problems to learn much more than i've told you. Seems to me though that if neither the house battery or power converter is feeding the 12 v. systems, there's probably a fuse somewhere that's common to both feeds. I'll have a look at mine and see if I can learn something that might help.

Andy
 

autostaretx

Erratic Member
Just another note: for many things involving 6v and 12v systems, a multimeter is not enough information
(it can tell you "voltage is here!", but it doesn't tell you "the batteries are draining....")

A handy tool (which is also a multimeter) is a clamp-on DC ammeter, such as this $60 Sears gadget (frequently on sale).
For detecting wanted and unwanted current drain, you clamp the clamp around the wire (no need to unplug/unwire things).
The meter then tells you how much current (up to 400 amps) is passing through that wire.

clamp-amp-side.jpg

Very handy with Sprinters for diagnosing glow plug and alternator issues, too.

--dick
 

tinman

Well-known member
If you have the Parallax power supply, beneath the fuses for all the 12 volt house equipment there is what appears to be an auto-resetting fuse in the battery supply circuit, or possibly on yours it's a manual reset. It's located beneath the circuit board that holds all the fuses. Check to see that it has power on both leads. if not, there may be a button you can push to reset.

Are you getting the 1-5 volts on the battery lugs on the circuit board? I'm wondering if possibly your two 6 volt batteries are not properly in series for 12 volt output. Maybe something to do with the light gauge ground wire you're suspicious of. That could cause strange behaviour from the converter output as well. You could try unhooking your batteries and connect the shore power.

Andy
 

HawksEye

Member
Interesting experiment:
Unhooked both 6V batteries.
Plugged into shore power.
Heard a LOUD noise coming from van I'd never heard before. In a panic that I'd fried something and was about to see my home light up with fire & smoke, I ran to the sliding door & fuse box, but the sound was coming from farther back. I ran round to the back door/battery compartments and discovered--- the TV is on. I've never turned it on before- never heard it make a noise before. Static coming out the speakers, and

the coach lights work.
The rooo-roooo-roooo-rooo noise is gone

will look under the fuse box for a switch.

I do wonder if that noise I hear when plugged into shore power is a converter fan...
[edits below]
so, converter is under the fuse box. I see a circuit board with some fascinating things on it, but no apparent switch.
 
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nutterbutter

2004 LTV Free Spirit T1N
Many free spirit users have complained about the battery draining over time. A few of the causes are powering the carbon monoxide detector, gas detector, lighted sofa switches, etc 24/7.

To remedy this, some people have installed additional/other battery disconnects.

I believe the 12v cutoff switch on mine (red knob about 12" above the floor into the cabinet) is a retrofit or otherwise been worked on. There's some odd caulk around it that doesn't have the LTV finished look. My red knob shuts everything off in the back: lights, control panel monitor (which would include propane on/off), 12v sockets, and the carbon monoxide and gas detectors. I usually shut everything down if I'm not going to drive for a while, as it does seem to prevent parasitic battery drain.

That all being said, you have to be open to the possibility that someone added a shutoff switch somewhere.

(my 2004 only came with the Mercedes installed single coach battery mounted under the passenger seat, so wiring is not identical to yours)
 

nekit

Member
This may be a stupid question, but did your coach have 2- 12v batteries before and did you change the battery cable configuration for the new 6v batteries? My Free Spirit is wired from the factory for 2- 12v batteries. If I wanted to install 6 V batteries I would have to change the cables so the batteries are in series, not in parallel?
Here's a link explaining how batteries are wired http://www.zbattery.com/Connecting-Batteries-in-Series-or-Parallel

If you just installed 2- 6v batteries your system only has 6v and that would explain the problems.

Just a thought. Hope it helps.
 

HawksEye

Member
good question, but I replaced 2 6V batteries with 2 6V batteries.
Same size, same compartments, same wiring.
I have the twin bunk version with the vented battery boxes mounted under the vehicle in the back-- one on each side, accessible via the storage area under each twin bunk.

One concern is with the connector on the end of one of the (+) battery cables. It had corroded down to almost invisible. I think I'll attempt to replace it today, but I have no formal crimping tool... just a vice grip.
 

GaryJ

Here since 2006
Without a crimping tool a battery cable end with self clamping can be used. They're available from any good auto parts store. Be sure to chase the corrosion in the cable all the way back to clean copper prior to attaching the new cable end. If the other cable ends look okay, scrape them out until they look new inside before reattaching. Poor contacting surfaces seem to be the cause of most electrical issues in 12V systems in general, and for sure with Sprinter and RV electrical problems.

Gary
 

tinman

Well-known member
I suspect your battery wiring is the issue, possibly a poorly executed conversion from two 12v. to two 6v. I don't have a separate battery cutoff, but the parasite draw seems to be eliminated if I remember to turn off the power at the master panel above the sliding door. My latching relay is also a bit wonky, and develops a voltage drop if I don't recycle it occasionally.

Andy
 

HawksEye

Member
Thanks, all for your help. There is not enough extra wiring for me to feel comfortable slicing off the ends and attempting to install new connectors. I just don't think it will be long enough to reach the battery terminal. I'm also suspicious of an odd appearing ?splice? in the cable. I'm gonna take it in and have them trouble-shoot the battery wiring and test out the converter. But y'all gave me some great help.
Much appreciated!
 

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