2007 Montana Big Sky Monitor Panel Malfunction

[snoobler]

Yes. I know. They're not accurate, rarely are. However, this is the first of 5 RVs owned that didn't have a functioning monitor panel. Regardless of accuracy, one can build a "relationship" with the gage and get a better feel for one's tank situations.

Initially, this was going to be a "WTH? is going on here," but it appears I managed to get a likely solution.

Recently acquired. Regardless of button pressed, we get this:



2/3 never lights up, and all buttons result in those 4 of 5 lights.

I managed to get it apart and identify the circuit board. Managed to get KIB's number off Google maps, and I'll be danged if I didn't talk to the most helpful service manager on the planet.

Walt was awesome. He identified the control board I needed and confirmed that 2/3 was definitely burned out and sent me wiring diagrams and troubleshooting info.

Pins 1 and 2 are +12V and ground. They should read battery voltage. anything under. If any pin gets no signal, it shows empty. If battery is under 12.5V, it should NOT show full.

I used patch wires such that only pins 1 and 2 were connected. Behavior stayed the same. Battery is 12.3V (yes, I need to charge it), so "F" should not have been displayed.

Here's a quick video of the behavior with only power applied:

https://photos.app.goo.gl/zeZbEb1GfGmxXaTv9

Only "E" should illuminate for any tanks.

So, high confidence this is a bad control board.

P/N SUBPCBM28

$18 + $15 shipping direct from KIB.

Walt spent at least 30 minutes on the phone with me explaining how things worked and taking my order. 5 stars.

Once I have everything sorted, I'll post the docs.

[travelin texans]

From my experience if you're plugged into shore power the battery monitor WILL read F as you're reading the converter. Disconnect shore power then in about 30 minutes check the monitor again, does it still show F?

[chuckster57]

A quick way to check the converter when I was doing PDI’s was to turn on as many lights as needed to get the “battery” lights to read 3 or less. Then plug in and look for 4 lights.

[snoobler]

I wasn't on shore power. Per the post, battery voltage was 12.3V between pins 1 and 2. On that basis, "F" should not have been lit.

Furthermore, with all of the other pins disconnected, no tank should have read anything but "E" yet E, 1/3 and F illuminated with the press of each tank button.

While I may discover new issues, the control board is definitely faulty.

I'm concerned the Atwood converter is on its way out too. After the monitor panel tests, I ran the genny briefly to run the converter to charge and to check if the fridge ran on AC. Yikes. I pulled the vent under the stairs, and the converter fan was completely blocked off. It was sitting at 13.4V, and the battery was at 12.8. Horrific voltage drop considering the relatively short distance. I'm almost tempted to move the battery into the heated basement. I'll probably swap out the converter with a powermaxx PM3-12 LK as I have a spare.

Anyway, have since discovered a leaking galley tank and a leaking black tank valve (poo drip). Based on Google Fu results, the galley tank is semi-common with these units.

Both rear slides need adjustment. They're not sealing at the top.

She's all fun and games while you're out on a date, but you bring her home, and you get to know the real her.

Still pretty darn happy with it otherwise. Even in its current state, it's usable for our purposes, though I would like to get the tank and poo valve fixed.

[chuckster57]

Valves are relatively easy to fix. Probably just the seals. You will have to know size and brand. Valterra and Bristol are the brands and the seals are NOT interchangeable.

Valterra “BladeX” will fit regular valterra. Bristol has to have Bristol seals.

What type of slide mechanism is on the ones that don’t seal?

[snoobler]

Originally Posted by chuckster57

Valves are relatively easy to fix. Probably just the seals. You will have to know size and brand. Valterra and Bristol are the brands and the seals are NOT interchangeable.

Valterra “BladeX” will fit regular valterra. Bristol has to have Bristol seals.

What type of slide mechanism is on the ones that don’t seal?

Thanks.

The prospect uncovering the bottom of it is pretty daunting, so I'm inclined to punt to someone else. I'll keep the brands in mind for the future.

I don't know that I can identify the type of slide mechanism. This is a 340RLQ with the hydraulically actuated 4 slides (1 switch, hold to extend). The two main rails supporting the slide have teeth on the bottom of them. The slides meet at the bottom, but have a small gap at the top. I've had to adjust the slide on our American Star, and I presumed it would be the same with the adjuster bolts at the corners - loosen the bolts, lower the slide until sealed, tighten bolts, check function.

[chuckster57]

Only difference in your method of slide adjustment is we do it with the slide 1/2 way out, then extend..check seal and then retract. It takes pressure of the slide mechanism when you move things “in the middle” rather than at the end of movement.

[snoobler]

Originally Posted by chuckster57

Only difference in your method of slide adjustment is we do it with the slide 1/2 way out, then extend..check seal and then retract. It takes pressure of the slide mechanism when you move things “in the middle” rather than at the end of movement.

Excellent. Thank you. I'll do it that way. Makes a lot more sense not having it cantilevered all the way out there.

[snoobler]

Looks like the control board was the culprit.

https://photos.app.goo.gl/E5EYjTpC6XxJELfw6

I was plugged into shore power with the furnace blower running. With only 2 lights showing for the battery (and confirming this thing seems to have consistently low voltage), I'm all the more concerned about my 45A Atwood converter and/or the wiring. I have a Powermax PM3-55LK at the ready to swap it out.

Slide adjustment was uneventful. Ended up tweaking 3 out of 4 of them. Thanks for the tips.

Steve

[flybouy]

Originally Posted by snoobler

I wasn't on shore power. Per the post, battery voltage was 12.3V between pins 1 and 2. On that basis, "F" should not have been lit.

Furthermore, with all of the other pins disconnected, no tank should have read anything but "E" yet E, 1/3 and F illuminated with the press of each tank button.

While I may discover new issues, the control board is definitely faulty.

I'm concerned the Atwood converter is on its way out too. After the monitor panel tests, I ran the genny briefly to run the converter to charge and to check if the fridge ran on AC. Yikes. I pulled the vent under the stairs, and the converter fan was completely blocked off. It was sitting at 13.4V, and the battery was at 12.8. Horrific voltage drop considering the relatively short distance. I'm almost tempted to move the battery into the heated basement. I'll probably swap out the converter with a powermaxx PM3-12 LK as I have a spare.

Anyway, have since discovered a leaking galley tank and a leaking black tank valve (poo drip). Based on Google Fu results, the galley tank is semi-common with these units.

Both rear slides need adjustment. They're not sealing at the top.

She's all fun and games while you're out on a date, but you bring her home, and you get to know the real her.

Still pretty darn happy with it otherwise. Even in its current state, it's usable for our purposes, though I would like to get the tank and poo valve fixed.

Based on the bolded statement it sounds to me like a bad battery or corroded cable or cable connections. I'd suggest checking cable connections and the battery ground connection on the frame first. If after cleaning connections and confirming the ground you get the same readings pull the battery and have it load tested.

[snoobler]

Originally Posted by flybouy

Based on the bolded statement it sounds to me like a bad battery or corroded cable or cable connections. I'd suggest checking cable connections and the battery ground connection on the frame first. If after cleaning connections and confirming the ground you get the same readings pull the battery and have it load tested.

I've load tested the AGM deep cycle battery. It's in reasonable shape in that regard. No idea how much capacity it actually has. The previous owner replaced it just a few months back as they were prepping it for sale.

Good call on the wiring. There is evidence of cable corrosion at one of the converter attach points. I'll dig into that more. Even with perfect connections and what I estimate to be 4awg wire, I'm looking at a 0.3V drop at 13V and peak current. Not great.

I'm still convinced something is wrong with the Atwood converter. It was 12.4V AT the terminals with negligible loads. When I unplugged it and plugged it back in, it was 13.4V.

The Powermax I have is 55A and can operate as a 3 stage charger or as a constant voltage supply. Since we're not cycling these batteries, I'll likely set it to 13.8V as that's the "standby" float voltage for the installed battery.