Electrical issue

[Mikehbar]

I have a strange electrical issue that has me baffled. When I switch the main interior lights on, it blows a fuse. When I push the awning in button, the main lights work, even with a blown fuse. I detached all the wires from the awning switch and the main lights work as they are supposed to.
Can the awning switch have gone bad even though it works to roll out the awning and retract it as well and is somehow shorting the main light switch via a common wire to both switches?
Any help would be appreciated.

[madmaxmutt]

Originally Posted by Mikehbar

I have a strange electrical issue that has me baffled. When I switch the main interior lights on, it blows a fuse. When I push the awning in button, the main lights work, even with a blown fuse. I detached all the wires from the awning switch and the main lights work as they are supposed to.
Can the awning switch have gone bad even though it works to roll out the awning and retract it as well and is somehow shorting the main light switch via a common wire to both switches?
Any help would be appreciated.

Do you have some kind of remote control system that controls both of those?

[Mikehbar]

No, i do not.

[Shokyle1]

I would guess short awning to lights some where. Is the fuse for the lights smaller than the fuse for the awning. If so maybe when it powers the awning and the lights it is over the fuse rating and that is why it pops.

[Mikehbar]

They are both 15 amp fuses. The breaker pops on its own as the awning switch isn’t activated when it goes. In fact, when the awning switch is pushed to retract the awning, it works properly and the main lights go on simultaneously.

[Shokyle1]

Very odd. Are your lights led? Led are polarity sensitive where incandescent are not.

[Cavie]

You need an electrician or someone that knows how to use a voltmeter. You have a problem with the wiring. I'm gonna guess that the awning and the lights are not on the same circuit.

[Mikehbar]

Yes they are led lights. Correct, they are not on the same circuit.

[Mikehbar]

If I can’t find the short could I pull the hot wire from the awning switch, secure it somewhere and run a new hot wire to the awning switch?

[Shokyle1]

Does not sound like it is in the feed circuit to the awning switch due to the lights only working when you operate the awning.if they only come on when the awning button is pressed in i would start with that wire. First place I would look for a short is the control panel, behind mine is a wiring mess.

[Mikehbar]

Makes sense. I’ll start at the control panel then check under the motorhome.

[Mikehbar]

I am in the wiring jungle behind the control panel and nothing is obvious yet. Since it’s the black wire on the awning switch that is the culprit, it makes it super difficult to trace it since there are multiple black wires back there.
Here is an interesting find. When I pull the fuse for the awning, it still pops the main light fuse when that switch is turned on. The only way it doesn’t pop is when I disconnect the black wire from the awning switch whether the awning fuse is in or not.

[Shokyle1]

Just a shot in the dark I would look at the wiring at the awning pivot points. Could be the switch but very odd that the awning operates correctly.

[JimD]

It appears the wire that feeds the light circuit is somehow connected to the awning switch circuit. These circuits should be totally independent of each other.

I am just guessing but this cross connection may be at near ground potential when the awning switch is not being used. Maybe the connection is somehow being routed through the motor windings when the motor is in a static state. This would cause the fuse to blow.

Did this all of a sudden start to happen? Has anyone recently played with the wiring? Are the switches next to each other?

You will have to find the connection between the awning switch and lighting circuit. Make sure there are no extra wires connected to or touching the awning switch terminals.

The reason the lights come on when the awning is activated is that 12 volts is then being fed to the lighting circuit via the wire that feeds the awning motor. Somehow these things are connected together. If the switches are near each other I would look there first.

[Mikehbar]

Sorry for delay in response as I had to step away from it for awhile. Anyway, everything was working fine for 3 plus years. No messing with the wires and the switches are very close together. I have taken the switches out and inspected the wiring and found nothing.

[GotRust]

Very strange things can happen when a ground is loose. Good luck.

[craigav]

Originally Posted by GotRust

Very strange things can happen when a ground is loose. Good luck.

I agree, as if you haven't made any changes then it is likely that something came loose such as a ground wire. The reason the fuse may be blowing is that the circuit for the lights are backfeeding into the awning motor.

[craigav]

Originally Posted by Mikehbar

I have a strange electrical issue that has me baffled. When I switch the main interior lights on, it blows a fuse. When I push the awning in button, the main lights work, even with a blown fuse. I detached all the wires from the awning switch and the main lights work as they are supposed to.
Can the awning switch have gone bad even though it works to roll out the awning and retract it as well and is somehow shorting the main light switch via a common wire to both switches?
Any help would be appreciated.

Do you have a VOM (voltage-ohm meter) and familiar with how to use it? If not, the first place I would check w/o a meter would be the 12v fuse panel where there should be a ground terminal bar connector, one of those wires there (usually the larger white wire is the one for the primary ground to the chassis) which may have come loose from its connection. Your fix in that case may be as simple as removing the wire, cleaning it with anything you have (a knife or sandpaper for example) and then clean the connection on the ground terminal and tighten it back down. Keep in mind that the other end of that connection could also be the issue (where that wire connects to the chassis or battery).

In fact that is what I would check first with or w/o having a meter. If that didn't resolve the issue, then I would use the meter and check and see if the light circuits is/are making a good connection to the ground which is simply the chassis ground. To do that test may require you have some additional wire (speaker wire is ok) and run a ground wire to the - negative post on the battery and have the light fixture and the ground wire you ran close enough to each other to use the meter and check for continuity between the light and the ground.

Check the 12v fuse panel ground connection first and if needed I can try to add more detail to how to use a meter to track down where the problem may be. ~CA

[craigav]

Keep in mind, with an RV 12v circuit, the wire colors are different than what you may expect ~CA

Black = (+) positive
White = (-) Negative