water pump wont stay on

[Rick Daniels]

strange issue this morning.  All of the sudden none of the water pump on/off switches will turn the water pump on unless you hold any one of the switches on.  If I press and hold the switch the pump stays on until I release the switch and the pump shuts off.  Clearly the pump is working but I cant run water unless I press and hold any one of the switches.  When I let go, the pump shuts off.  I cant connect to city water due to sub freezing temps so I have to rely on the pump to draw water from the fresh water tank. Advice would be appreciated.

[Bill Lampkin]

Look for a pump controller like this: it may be close to the water pump. Replace the controller and you should be good to go.

https://intellitec.com/water-pump-control/

[Rick Daniels]

Thanks Bill Lampkin, however an earlier post on the forum by Fred Brooks indicated that that device was not used until Monaco took over. I have never seen one of those in my coach.  Until I find a fix I have to find someone to hold the switch while I shower or go without which is not an attractive option.

[Fred Brooks]

Rick,
The SMC era coaches had their own version of a multiplex controller. Inside the water pump & plumbing box, you will find the 12 volt "hold relay". I cannot tell you which one it is because I have not seen one fail. A test light should identify the respective relay. Merry Christmas!

[Bill Lampkin]

To find the relay, just trace the power wire on the pump back to the relay.

[Fred Brooks]

   Actually the 2 relays on the top of the box are the ones you are looking for. One is the trigger relay and the other is the hold relay. When you push the momentary switch upward, the trigger relay activates the "hold relay" which turns on the pump. When you push the momentary switch downward, the "hold" relay deactivates. Fred

[Rick Daniels]

In the event one or both are bad how would I identify the part number or brand to search for a replacement?  Any thoughts on a source?

[Bill Lampkin]

Those relays are standard automotive relays; NAPA or any parts store will have them.

[Rick Daniels]

Interesting observation.  I find only one relay near the water pump.  Also there  three wires not connected to anything that do not go to the water pump directly. Some, if not all go into the water bay.  They have been there and have had no purpose since I have owned the coach.  Anyone know what they might have been for?

[Fred Brooks]

    Rick, I have the same 3 wires not connected to anything. If all you have is a single relay, and the red wire from the pump is going to that relay, take a picture or two. Then remove the relay and note the amperage on the top and any Autoparts house will have it. Fred

[Rick Daniels]

brand new matching relay, water pump will still not stay on without holding the switch.

[Fred Brooks]

   Rick, how many remote water pump switches do you have? Do you have the same response from each of the switches. If you do, you may have a ground issue. I will go to my coach tomorrow and see if I can duplicate the issue you are going thru. One final question, when you are filling your fresh water tank, does it stop filling automatically when the tank level states it is "full" ? Fred

[Rick Daniels]

I have three switches in the coach; over the dining table, bath sink and lav.  There was one in the water bay but that one has been out of the coach for a couple of years.  And yes, the fill switch seems to shut off when tank is full.  I say "seems" because I monitor it and when the indicator says full, I switch it off.  Necessity is the mother of invention.  I recalled my "Red/Green" methods and have engineered a emergency system that now allows me to shower and do dishes without having to call the neighbor over to hold the switch.

[Fred Brooks]

   Thanks Rick, Cool idea with the stick in the wall trick. I'll try and figure out a PCR (problem, cause, remedy) tomorrow. I am not sure if all the switches are daisy chained together and something has become disconnected or a lost ground wire. I'll try and draw up a schematic of the logic once I figure it out. Fred

[Bill Lampkin]

Rick, if there are two relays side by side, try replacing the other one. As Fred says, the second relay creates a 'latch' circuit that will run the pump once you let go of the switch.