12-volt issues

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napalm204

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Aug 3, 2009
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I got some feedback the other day for an issue I am having inside my coach.  When I plug into shore power and turn on the battery disconnect some of my 12v lights will work but most do not.  Why would four work and six will not?  Could it be that I have six bad switches fail all at once?  I know the bulbs are good because I tried them all in one of the fixtures that is working.  I have pulled the fuses and inspected them one by one and they are all good.

I will see if the sockets are hot and if they are it must be bad switches.  But six going out all at once seems too coincidental to me.
 
Just pull the switch out and run a jumper across the pins. A wide screwdriver may work.  Anything metal
 
Rene-  I used my multimeter and found power to the 12v light that is working.  I found no power for the light next to it that is not working.  That puzzles me.  I have checked fuses and they are all OK.  What do you think my next check should entail?  Any suggestions from anyone on the Forum are all appreciated. 
 
Ok, you have power to some light switches but not others.. First, check BOTH terminals on the switch.

Next.. Many times lights in the same area will have the same ground and/or power feed

Broken wire
Loose screw
Connector not connected on the back of the fuse panel
Wire Nut came off and wires went fly about.

 
Ten lights on one fused circuit seems like quite a bit to me (10 x 1.5a). Perhaps you have two fused circuits with four lights on one string and six lights on the other.

Check all of your 12 vdc fuses with an ohmmeter. If they are OK, open the fuse panel so that you have access to the back of the fuses. Use your DC volt meter to check both the voltage input and output of each fuse. Also check each connection to the fuses and look for any wire that may have become disconnected from the fuses.

If all checks OK, open each of the six switches for the lights that don't work and check for DC voltage on each side of the switch. Since the DC to those six lights may be daisy-chained from one switch to the next, start with the switch that is closest to the fuse panel.

If you have DC at the fuses but not at any of the switches, then you will need to trace wire from the appropriate fuse to any connection points between the fuses and switches. If you can't find a "logical" place where they might have mounted a connection box or pull the wires to determine where one might be, you will need the circuit plans to continue.
 
Joe,
Before I start going to far. When you said that you turn the battery disconnect on, do you mean you disconnect the battery or are connecting it? I've had many people misunderstand this and have even seen it labeled or wired wrong, no ones fault, just because there are so many manufacturers. I'll explain a little more but I need to know if you disconnect the battery and the lights go out our if you connect it and they go out?
 
The light are most likely wired in a daisy chain arrangement. Start with the working and non=working pair that are closest to each other, Look for a bad, loose, or broken connection, either at one of the light fixtures or at the one of the switches.

Joel
 
Marky B said:
Joe,
Before I start going to far. When you said that you turn the battery disconnect on, do you mean you disconnect the battery or are connecting it? I've had many people misunderstand this and have even seen it labeled or wired wrong, no ones fault, just because there are so many manufacturers. I'll explain a little more but I need to know if you disconnect the battery and the lights go out our if you connect it and they go out?
Click to expand...
Fleetwood is one of the biggest offenders in this regard.  My Disconnect switches are labeled ON and OFF.  It can get very confusing when trying to describe to someone, when ON, means the Batteries are ON (connected) and the Disconnect is OFF.  Some RVs use the nomenclature of USE and STORE, which makes a lot more sense IMO. 
 
napal204, why do you feel that you need to turn on the battery disconnect switch when you hook up to shore power?  This is not necessary, but try turn on the battery disconnect switch before you hook up to shore power.
 
LOL. I always though that On and Off were OK labels for the disconnect switch.  I believe for the typical RV owner, ON means power is on and OFF means power is off.  It's only confusing if you over-think it, trying to map the internal workings of the circuit to the external labels. That's something us technical types need to know, but not the operator of the switch.
 
Another possible issue.. In my RV there are several lights with multiple switches

Ceiling lights in the Main living area are controlled by a pair of 3-way switches (one by the door) this covers 3 ofthe 4 lights (the onnear the sink only has the built in switch) all the lights have built in switches as well.

If either the 3-way OR the device switch are off... no light

Bedroom ceiling light has a single switch on the wall, and the device switch

So does bathroom lights (both of them

And the "Dome Light" (Light switch (Vehicle) and itself)

This can be confusing as I've gone and turned on a light and though OH.. S***! only to find it was nothing more than the switch on the wall... or device (The other switch).
 
Gary RV Roamer said:
LOL. I always though that On and Off were OK labels for the disconnect switch.  I believe for the typical RV owner, ON means power is on and OFF means power is off.  It's only confusing if you over-think it, trying to map the internal workings of the circuit to the external labels. That's something us technical types need to know, but not the operator of the switch.
Click to expand...
Laugh all you want to, Gary, but when the switches are labeled "Battery Disconnects", I hardly think it's intuitive to a new user that Disconnect ON really means Battery ON (disconnect off).

Example; read cgmartins's earlier reply, and tell me if he considered Disconnect ON to mean Power ON or Power OFF.

I'm willing to bet that even the all knowing Gary Roamer discovered that Disconnect ON = Battery ON (not disconnect ON), by observation of results, and with mild surprise, the very first time those switches were encountered.
 
Nothing like trial and error to resolve an ambiguous situation :)
 
What, common sense in RV design?  What a concept!
 
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