Black/Gray tank sensors

[harrelljones]

Hi All, I have a 2007 25fb. I've owned it 4 years and have about 150 nights and 12000 miles on it. We've made several upgrades/updates to it and it is wonderful. The one thing that still bugs the hell out of me is the sensors for these tanks. For instance I just emptied both tanks closed the the valves. Then put about 5 gallons of fresh water into the black tank and opened it and saw just clear water coming out. So I assume it is empty. The gage says it's about 3/8 full. Now have it parked in front of the house with a slight tilt toward the curb. Gauge reads 3/4 full and is red yet I haven't put a drop in it since I emptied it. Gray is not as bad but still not great. I've done the ice cube thing and that worked sort of. Thinking maybe time for some new Sea Level sensors. Thoughts? Thanks so much!

[Streamside]

Originally Posted by harrelljones

Hi All, I have a 2007 25fb. I've owned it 4 years and have about 150 nights and 12000 miles on it. We've made several upgrades/updates to it and it is wonderful. The one thing that still bugs the hell out of me is the sensors for these tanks. For instance I just emptied both tanks closed the the valves. Then put about 5 gallons of fresh water into the black tank and opened it and saw just clear water coming out. So I assume it is empty. The gage says it's about 3/8 full. Now have it parked in front of the house with a slight tilt toward the curb. Gauge reads 3/4 full and is red yet I haven't put a drop in it since I emptied it. Gray is not as bad but still not great. I've done the ice cube thing and that worked sort of. Thinking maybe time for some new Sea Level sensors. Thoughts? Thanks so much!

Yep. Sensors go bad. I have a 07 27fb and took the plung(not plunger) and replaced both black and grey sensors. Not too bad if a job, After emptying, back flushing and getting the tanks as clean as I could, started the process. Just make sure the tanks are empty before starting. There are several threads out on how to do this job and make sure to get the replacements prior to starting. Took about an hour for each tank and sensor.
Btw, I did repair some of the styrofoam insulation while the tanks were dropped. That time was extra.
Best….
Oh, after I replaced the sensors, I could not figure out how to recalibrate the gauge. As it turned out, I did not need to. But when I was doing my own manual calibration, putting in 5 gallons at a time, I did find out that my grey tank was smaller than what the documents said. But now I have real data to go by

[Streamside]

Originally Posted by Streamside

Yep. Sensors go bad. I have a 07 27fb and took the plung(not plunger) and replaced both black and grey sensors. Not too bad if a job, After emptying, back flushing and getting the tanks as clean as I could, started the process. Just make sure the tanks are empty before starting. There are several threads out on how to do this job and make sure to get the replacements prior to starting. Took about an hour for each tank and sensor.
Btw, I did repair some of the styrofoam insulation while the tanks were dropped. That time was extra.
Best….
Oh, after I replaced the sensors, I could not figure out how to recalibrate the gauge. As it turned out, I did not need to. But when I was doing my own manual calibration, putting in 5 gallons at a time, I did find out that my grey tank was smaller than what the documents said. But now I have real data to go by

Btw, you really don’t have to drop the tanks all the way. I used a floor jack to hold up the pan that I was working on, removed all bolts on the fore, aft, and road sides, just loosened a few turns the bolts holding the pan on the curb side, worked the plastic flaps loose around the drain valve handles, then slowly lowered the tank cover so it dropped a few inches below the drain lines, the sensors were on the side of the tank very close to the drain line outlet. Used a adjustable wrench to loosen, after unclipping the telephone wire, Teflon taped the new sensor, screwed it in and jacked the pan back up. My tanks never moved.
Best…