2002 Holiday Rambler 2nd rear black tank

Ok,found out what it is. There are two black tanks, one valve. The smaller tank in the bathroom has a toggle switch that is labeled vacuam pump. On rv repair guy, hubby and I toggled it and it did make a very loud noise, but, did evacuate the fluid in the tank. But, we all thought, that was for emergency only, when the regular flush handle didnt work. Well, the rv dealer we bought from found the owners manuals and schematics , we finally found out that the vacuam pump has to be on at all times. The noise we heard does turn off after about 20 seconds.(we never left it on that long) The pump pumps out the waste from the smaller tank to the larger tank. (((Shaking my head, so much to learn))) Thanks for your help all.

Chances are the black tank goes to one dump valve...there could be a clog in the line to that...or the vent to the roof could be clogged...

1. Call HR support with your VIN # and Coach #....they should be able to look up coach and tell you if there is a 2nd dump valve or there is one master black tank...if it is one drain, then I bet you may have to get on roof and make sure vent is clear...Once all is clear, you can test the black tank for that toilet by holding button for six seconds, this will over ride the red and if tank flushes, then you are down to the sensor or a good tank clean.

Just thinking through the problem with you..... If it was my rig, and I could not find a dump valve for the second tank, I would disconnect the external water source, turn off the internal fresh water pump so that no water would flow when I opened the toilet valve, hook up the sewer hose to a dump/sewer cleanout, open the sewer dump valve and let anything that will come out drain thoroughly, pour a pitcher or two of water into the affected toilet, open its flush valve to let the water go out and see if any water came out of the sewer hose outside. That will tell you if there is any connection between the 2nd tank and the primary black tank dump valve. If water DOES come out, then you probably just need to do a really good flushing of that second tank. BUT...I wouldn't try to do any flushing until I had determined that it was connected to the an open sewer valve. If you put water IN and it doesn't come out anywhere after doing the above, then yes, I would say remove the tank to see what's going on.

Endeavor is a 2002, yes, two toilets. We did find something online, last night that noted the red light meant the tank is full, but, is it? I will have to look for the sensors. There are two waste dump valves,only, for black and grey. Black and grey tanks have been dumped. Hubby and I found the smaller black tank, and yes, it is logical that it would have a separate dump valve, but, we could not find it. The place where we bought the motor home from, actually sent their mechanic to our house to check out what was going on.

(We flooded during Harvey, we are in a hotel still, trying to get into the motor home, once everything is working. Motor home is in front of house, until house is put back together. Can't move in there, until we get the lovely odor figured out)

He couldn't find a separate dump valve either, nor could he get the red light to go off. Now, he is talking about removing the smaller tank.to see what is going on.

When you have 2 Black tanks, they are NOT connected to each other. Each tank has its own dump valve. As the other poster stated, the RED light means the tank toilet sensor(NOT the same sensor as the tank fluid level) is registering the tank is FULL and the toilet will not flush. This sensor prevents the user from overfilling this Black tank because the toilet has its own waste pump that grinds and pumps the debris to the tank. Since you have an odor, that probably means the tank is full and has OLD waste in it. OR, the tank is almost empty and was not properly maintained and flushed and dumped and the build up of debris has tripped the FULL toilet sensor. These sensors for the Toilet are glued to the exterior of the tank and are not into the tank like other probes. There are usually 2 glued on sensors. 1 for half and 1 for full. Doug

2nd rear black tank?????

DO you have TWO toilets?

What Model is your Endeavor?





In your waste compartment should be TWO waste dump valves going into a common drain connection for sewer hose
Large drain line/Valve is for the Black Tank
Smaller drain line/valve is for the Grey Tank

Just one of each

Blinking light for toilet means black tank is FULL (or sensor is registering full) and therefore no toilet electric flush (can manually flush via 'knob' on backside of toilet (some models need a wrench)

But make sure Black Tank is dumped and showing EMPTY before manually flushing toilet