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cat 259d3 filter pump not working

ole repairman

New Member
Joined
May 26, 2022
Messages
2
Location
Atlanta
Drained water separator bowl on bottom of filter to ck pump operation with refilling of bowl.With key on pump didn't run.Removed pump and direct wired to battery with no life from pump.Also cked connector with no power to pins.Supposing ecm times power to pump but should run to refill filter and bowl.Possible short in addition to bad pump.Anybody have advice or info?
 

Acoals

Senior Member
Joined
Dec 15, 2019
Messages
1,854
Location
Wisconsin
Occupation
Jack of all trades/Master of none
Those pumps are a common fail item, but you have to have power to run in any case. Check the fuse and wiring, and if there isn't anything obvious ask Nige for a wiring diagram.
 

ldequip

Member
Joined
Mar 4, 2025
Messages
22
Location
Hagerstown MD
i have had same deal. as i understand it that electric pump runs for about 30 seconds after key goes on. they are not running the rest of the time the machine is on. so when they fail you don't know until you change the filters.
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
38,779
Location
G..G..G..Granville.........!! Fetch your cloth.
as i understand it that electric pump runs for about 30 seconds after key goes on.
You are correct. The electric pump is only designed to fill the system after a filter change. If the key is turned to ON the pump should run for about 30 seconds then stop. If the key is turned straight to the START position the pump will not run at all.

I would suggest that you try backprobing the connector at the pump and check it is live for a short period when the key is turned to ON.

Electrical schematic on the way to you.
 
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