12 Volt System Problem?

[gator67]

I had recently made a post about our LP Gas detector blinking rapidly green, a condition not documented in the manual. Atwood had never heard of that either. Removing the 1 amp fuses, and pressing the "test" button did not have any effect. Turns out it seems to be a symptom of a larger problem.

Shortly after that, my wife noticed that the red light next to the button to
turn on the gas water heater was faintly blinking rapidly, even though the water
heater button was in the off position. I turned on the gas water heater switch and the blinking stopped, and the water heater ignited, but the red light never came on solid, as it used to (as it preps to ignite). Even more weird is that when the gas water heater button is in the "on" position, there is NO power to the LP gas detector!

I switched off the chassis battery and house battery switches for 1 minute and turned them on again hoping to reset something, but it made no difference.

These are the only symptoms we have noticed so far. Any ideas?

[gator67]

I had recently made a post about our LP Gas detector blinking rapidly green, a condition not documented in the manual. Atwood had never heard of that either. Removing the 1 amp fuses, and pressing the "test" button did not have any effect. Turns out it seems to be a symptom of a larger problem.

Shortly after that, my wife noticed that the red light next to the button to
turn on the gas water heater was faintly blinking rapidly, even though the water
heater button was in the off position. I turned on the gas water heater switch and the blinking stopped, and the water heater ignited, but the red light never came on solid, as it used to (as it preps to ignite). Even more weird is that when the gas water heater button is in the "on" position, there is NO power to the LP gas detector!

I switched off the chassis battery and house battery switches for 1 minute and turned them on again hoping to reset something, but it made no difference.

These are the only symptoms we have noticed so far. Any ideas?

[Old Scout]

"Once upon a time" I was switching out/cleaning my house and engine batteries and forgot to reconnect the ground cable between the two banks. The result was all kinds of blinking lights/beeps from the detectors. So maybe you have developed a grounding problem....dean

[gator67]

Here is more information/analyisi of the problem.

I did an extensive analysis of my flashing LP gas detector and here are some of my observations.

I will call the red light next to the water heater switch, the "water heater light"�.

I observed that the position of the water heater switch did not have any effect on the conditions, so I will not mention that any further.

I removed the LP gas detector. There is a green wire connected to the red wire on LP gas detector, and a black and a white wire connected to the black wire of the LP gas detector. There were 12.6 volts across that connection, so the voltage was apparently okay.

When the LP gas detector was connected, there were 3.4 volts going to the water heater light, thus accounting for the faint flashing of that light. When the wires were disconnected from the LP gas detector, there was NO power to the water heater light and, obviously, the flashing stopped.

It appears that the water heater light and the LP gas detector are somehow wired in sequence.

According to all the fuse diagrams, the LP gas detector is on a 1-amp fuse. Removing all the 1 amp fuses did not turn off the power to the LP gas detector. However, removing the 7.5 amp fuse, which it says is for the Kingdome, DID cut off the power to the LP gas detector.

If you look at the 12V fuse and wiring schemes in the Alpine Coach Owner's Manual, you will find a very different scenario. That diagram shows the LP gas detector on its own 1 amp fuse, and the Furnace-water heater 20 amp fuse having the furnace, DSI (water heater light) and water heater on it. It appears to me that the coach has been miswired.

I bought a NEW LP gas detector (same model) and installed it. All the symptoms were the same... flashing green light on the LP gas detector and faint flashing red on the water heater light.

I tightened all the battery connections, in case it might be a grounding problem, but I understand there are several grounds in the circuit so it may be somewhere else.

[gator67]

Just to close the loop on this...

I had a repair person come over and diagnose the problem. He suspected a bad ground wire, so he removed the ground wire attached to the ground side of the LP gas detector and joined in another one from somewhere else and now all works fine.