Can't find access to gas tank sending unit

[jshack]

My gas gauge on my 2004 240 Sundancer stays at empty regardless of the amount of gas in the tank (69 gal. tank). The next thing to check, I think, is the condition of the tank sending unit, but I cannot figure out how to access the top of the tank to check the sending unit. I removed the 10 gal. fresh water tank and I can see some of the gas tank (gas outlet, fill and vent lines) but the tank appears to run forward under the deck and I have no additional access covers or deck plates to remove to gain access. What is the trick to gaining access to the sending unit? Do I need to remove seats or gain access from the rear berth? At this point, I'm out of ideas, any help will be greatly appreciated, thank you.

 

[Lazy Daze]

If you can't get at it from the bilge, then try removing the center panel under the mid-berth "floor" - under the bed cushions.

 

[DaleM]

I know not the same boat but on my 280 the access to the tank was similar to what Dennis mentions. I would remove the cushions in the rear berth area and there was a round cover that screwed down. Under that was the top of the tank sending unit and a WHOLE lotta gas.

 

[jshack]

That was it! Found it under the rear berth cushions. Grounded the pink wire and the gauge still did not move. Is there additional troubleshooting to do or, is it safe to consider the gauge bad? Thanks

 

[Bt Doctur]

try grounding the pink wire using a jumper from the neg post of the battery. Without the tank ground the fuel gauge wont work. Tanks should have a black ground and a green bonding wire

 

[jshack]

Grounded the pink wire to battery neg term and gauge did not move. Can I add gas while checking sending unit ohms and if the ohms changes, sending unit may be good and gauge most likely the defective part?

 

[Lazy Daze]

Did you have the key "on" while you did your check? Key must be in the on position.

Do the same "grounding" the back of the gauge.

Easier (and safer) to just pull the sender out and check resistance that way. But sometimes you will apply more pressure by hand and get a false positive.

 

[Bt Doctur]

If grounding to the neg battery did not move the gauge , go to the pink wire at the gauge and apply the ground there. No movement is a bad gauge, if gauge moves then sender wire to tank is open/corroded/ broken

 

[jshack]

I grounded the pink wire directly to the battery neg term, turned on the key and the gauge did not move off of empty. If I leave the key on a short while, the Smart Craft sends out a Fuel Level failure alarm? I measured the sensor ohms and had 240(empty) so, I added 10 gals. (69 gal.tank) and the ohms remained at 240. Is it possible that I have a bad gas tank sending unit and a bad gauge, how lucky can a guy get!

 

[jshack]

To close out this Thread, I replaced the tank sending unit today and that resolved the problem. I checked the ohms on the old unit and it appeared to be functioning properly (30 ohms at full and 240 ohms at empty) so, the only thing I can conclude is the the float is saturated and remained on the bottom, indicating an empty tank. Thank you for all your guidance and assistance.