Water pump has quit

roessler · 08-13-2002, 01:41 PM

'77 Excella 500, 31 ft, center bath. Finally, I thought, had enough of the bugs fixed to try it out. My son (the real owner) took it for a short vacation Sunday, called this morning that the water pump quit last night. Today he found a blown fuse (I guess on the 12 V board), had gone into town and got a fuse, put it in, but the pump still wouldn't run, fuse didn't re-blow.

Sounds like whatever blew the fuse may have also fried the motor. Have just order a Service Manual (finally), but in anticipation of having to remove the pump to either repair or replace, I'm looking for any advice that can help me out --- for getting to and removing the pump, or anything electrical that could be the real problem.

Craig · 08-13-2002, 02:15 PM

I'm only a novice, so I have no idea what other problems it may be. But as far as getting to the water pump and access to it, on my 78 Center Bath Excella it's in the wardrobe across from the bathroom and very easily accessible.

roessler · 08-13-2002, 02:40 PM

From previous work, I know the pump is behind the oven, and sort of behind and below the 12v fuse panel. My impression is that the oven/range will have to come out to access the pump. I hope I'm wrong.

sovereign · 08-13-2002, 08:01 PM

on my 77 sovereign,just as you come into the coach on the left beside my oven is a sliding door where you can get too my pump and oven. but mine is a rear bath/center twin layout

davidz71 · 08-14-2002, 01:12 PM

I will try to post pictures of my pump location, under the oven on my '77 Excella 500 rear bath.

davidz71 · 08-14-2002, 01:19 PM

Let's try again.

davidz71 · 08-14-2002, 01:21 PM

Another shot.

roessler · 08-14-2002, 01:38 PM

Thanks for the info and pix, however I know where the pump is, the problem will be getting access to it since its behind the oven, and can barely be seen looking through the opening just to the left after leaning in the door.

I was hoping someone would have some ideas on trouble shooting the circuit before I actually have to pull out the pump/motor. I am guessing the circuit goes from the fuse, then maybe parallel circuits through the ON-OFF switches on the Control Panel and in the Bathroom, then the pressure switch, finally the motor and ground, although maybe not in the order just said.

I think I'll start checking resistance to ground beginning wherever I can access the circuit, might get lucky and find a bad switch.

Does anyone have any experiece replacing the OEM pump/motor with a small centrifugal pump, or other style pump? It seems like just about any kind of pump will work as long as the gpm and discharge pressure are sufficient, and put a check valve on the inlet and/or outlet to keep up the system pressure. Comments?

davidz71 · 08-14-2002, 04:02 PM

On-off switch is in series with the power source to the water pump. When the switch is depressed to the on position, 12 volts should be present at the pump and the light illuminated. If the light does not illuminate, the switch may be defective. There should be continuity between the two terminals with switch in the closed position. Your fuse may blown or the holder has a short.
The red wire to my pump was loose on the pump so it would not always work.