Hi guys, my water bay had been leaking for some time, slowly getting worse and soaking the display board. I have found the leak and stopped it (thanks Tom!) however the board does not display any information. The board is now in my hands and all the components measure good but I cannot get a consistent read on the two switches (fresh water level, waste water level.)
The switches have part number 0030-201 on them, but I cannot find the right switch anywhere. Does anyone know where these might be available?
(08-10-2026, 04:18 AM)Jack Houpe Wrote: Dave is this a momentary switch? Please post a picture of the bottom of the switch where it is soldered onto the board.
It should be a momentary switch Jack. You push and hold it to see the tank level. I would want to test the leads on the board and jumper them to see if the switch is the issue.
Yea we need to see more pictures, how many terminals, any other markings?
Hi guys, yes. There are four terminals on each switch, and if I press and wiggle the switch it will change resistance from infinite to something much lower (but fluctuates wildly) on both switches - this is why I suspect they are ruined. Mechanical switches and water just don't get along that well.
But I can't find replacements is the issue. Shouldn't be this hard. Sigh.
(08-10-2026, 10:06 AM)dmsinnott Wrote: Here's a pic of the underside of the board.
To my eye it looks like they share a common trace on one side, that is most likely a power source, may be 12v it may be 5v who knows. But I am thinking you will see some sort of voltage on that side. The switch should then pass power to the other side it would appear. Just guessing here, you’re going to have to do some testing with a multimeter to see what you get. You could also try jumping across the terminals and see what happens. I would do this after taking your readings to see what you are dealing with. I would assume these boards are fed from a 12v coach supply voltage. Have you checked that you are getting that supply voltage to the board?
Looks like a bit off corrosion on the trace at the bottom, that connection looks a bit suspect.
I agree with Jeff. Looks to me like it is a double pole momentary switch but they are paralleled. The first thing I would do is take a wire brush and lightly clean the corrosion off, then re-solder those points. If you're uncomfortable with this, you can mail it to me and I will do it for you. I'm certain you'll be able to find a suitable switch if indeed these are defective.
I agree that they look to be paralleled, I also saw the corrosion and measured the traces from one end through every connection to the other end, all good. The only things that gave me trouble measuring were the switches themselves, which makes sense as mechanical devices exposed to water do not do well.
I'm looking for where I can get the replacement switches.
I also measured the resistors that are near what look to be hot spots on the board, they all match what they are supposed to be. Initially thought one or more of the resistors may have overheated and changed resistance, but they survived intact.
No issues with soldering, but I definitely feel the switches themselves are faulty.
Jack thank you very much for finding those switches (and offering to do some soldering for me!) but that's something I am very comfortable with (one of my oldest hobbies is tube audio, have been building/rebuilding stereo amplifiers and speakers since I was 13 ... I'm now 65)
One issue may be lining up the switches with the holes. as they will move a bit with just the two pins on the switch. I'll give it a shot!
Thanks again guys, I'll report back after new switches are in.
