Macerator Pump Coming on by Itself

[Newbie2016]

I tried to do a search on this and it came up with nothing. Please forgive me if this has been covered before. I am in a campground and using the Airforum app. Last night at 3:00 AM I was awakened by a terrible noise inside my 2016 Grand Tour. I finally determined it was possibly the macerator pump - it was running and then shutting off for a minute or so before starting back up. I went outside and opened the door (which was locked) and flipped the pump switch from off to on, then back off. That stopped it (but for how long?) What the heck? Has anyone else experienced this?

[Protagonist]

That's a new one on me.

If it really was the macerator pump then possibly the first thing to look for is chewed-up wiring leading to the pump. It can only come on by itself if there is a short-circuit in the control wiring. Small furry critters that don't know any better have been known to chew on an RV's electrical wiring.

In the meantime, you can always pull the pump fuse to keep the pump from activating when it's not supposed to.

[amirm]

It is a yellow 20 amp fuse. I know because mine blows every few months.

I suspect the switch-panel comes off with a few screws in which case I would take it off and check to make sure the wires have not come off and shorting out.

[BurntAsphalt]

Just trying to exhaust all the possibilities...Is it possible that the noise is the water pump cycling normally to keep water pressure and not the macerator?

[amirm]

Originally Posted by BurntAsphalt

Just trying to exhaust all the possibilities...Is it possible that the noise is the water pump cycling normally to keep water pressure and not the macerator?

For sure. Ours is doing that I just found one of the causes: a leaky joint behind the toilet.

[Air99]

Originally Posted by amirm

For sure. Ours is doing that I just found one of the causes: a leaky joint behind the toilet.

+1, the water pump is louder than the waste pump on my rig and located inside the van. It’s freaky in the middle of the night!

[Newbie2016]

Back from my camping trip. Thank you everyone for your input! Hasn't happened again so far. I do know for sure it wasn't my water pump, because I turned that off overnight. I haven't pulled the panel to check for loose wires - kinda scared to do that because I am afraid I might pull something loose myself. Not the most coordinated person in the world. I got down to check the fuse panel so I would know where to pull the fuse if it happens again. I have the 2016 Grand Tour Twin, so my panel is down near the floor underneath the rear of the driver's side twin bed. The label says Circuit 9, 20 amp, macerator pump, comp. & LP LTS. Does anyone know what comp. and LP LTS. might be? I want to know, since I will be disabling those two things too if I pull the fuse. The Interstate Guide only mentions the macerator pump on that circuit.

Susan

[Boxster1971]

Originally Posted by Newbie2016

Back from my camping trip. Thank you everyone for your input! Hasn't happened again so far. I do know for sure it wasn't my water pump, because I turned that off overnight. I haven't pulled the panel to check for loose wires - kinda scared to do that because I am afraid I might pull something loose myself. Not the most coordinated person in the world. I got down to check the fuse panel so I would know where to pull the fuse if it happens again. I have the 2016 Grand Tour Twin, so my panel is down near the floor underneath the rear of the driver's side twin bed. The label says Circuit 9, 20 amp, macerator pump, comp. & LP LTS. Does anyone know what comp. and LP LTS. might be? I want to know, since I will be disabling those two things too if I pull the fuse. The Interstate Guide only mentions the macerator pump on that circuit.

Susan

If you look at the schematic diagram on page 9-28 of the 2016 Owner's Manual it shows that Circuit 9 powers the macerator and the various exterior compartment lights. Have them disabled won't have much effect as the older Interstates didn't even have exterior compartment lights.

Hope this helps.

- - Mike

[amirm]

Originally Posted by Newbie2016

Back from my camping trip. Thank you everyone for your input! Hasn't happened again so far. I do know for sure it wasn't my water pump, because I turned that off overnight. I haven't pulled the panel to check for loose wires - kinda scared to do that because I am afraid I might pull something loose myself. Not the most coordinated person in the world. I got down to check the fuse panel so I would know where to pull the fuse if it happens again. I have the 2016 Grand Tour Twin, so my panel is down near the floor underneath the rear of the driver's side twin bed. The label says Circuit 9, 20 amp, macerator pump, comp. & LP LTS. Does anyone know what comp. and LP LTS. might be? I want to know, since I will be disabling those two things too if I pull the fuse. The Interstate Guide only mentions the macerator pump on that circuit.

Susan

You have the same Interstate as I. The "comp. and & LP LTS" is lights in the external panel/switches. So pulling that fuse should not disable anything that you need inside.

[Titus]

I was going to guess that LTS was an abbreviation for lights. Not sure about the LP and comp. But I could live without a few lights if that is what it took to get the macerator pump to behave itself.

[Protagonist]

Originally Posted by Titus

I was going to guess that LTS was an abbreviation for lights. Not sure about the LP and comp. But I could live without a few lights if that is what it took to get the macerator pump to behave itself.

LP might be related to the propane system, since LPG is another term for propane. But I don't know of anything lighted on the LPG/propane system.

No clue what "comp." is an abbreviation for. Unless newbie2016 has an Interstate with air suspension, in which case there is an air compressor, and "comp" could refer to that.

I suppose it could still refer to "compressor" even if newbie2016 doesn't have air suspension, because there's no compelling reason why Airstream would bother to make separate labels for the fuse boxes of vehicles with and without air suspension.

[amirm]

I was stomped by the abbreviation just the same and after lots of digging, I found out it was just the external indicator lights.