Hello, I've got a 259D3 CW901891 with the battery running down after 7 to 10 days. Does anyone have the Key Switch Circuit wiring schematic? What I've found so far: Battery voltage on chassis ground with key off. With the key off, and checked with a multi-meter, there is a current draw of 400 mA. Checked across the battery disconnect on the negative cable. When checked with test light the voltage/current draw flashes at 1 second intervals, turning the test light on and off. When the #10 in cab fuse "Key Switch" is pulled the draw dissapears. When testing across the #10 fuse, with a multi-meter for mV, there is no voltage reading. Any ideas on which part of the circuit could cause a load that would be flashing on and off, and which part of that circuit to check first? Thanks.
Check your message inbox for an electrical schematic. From that it should be easy enough to identify all the circuits that draw from #10 fuse.
Does it have a product link? Try pulling that fuse instead. But, I think what you're seeing is somewhat normal. Anytime you bridge the 'open' battery isolator, modules start to wake up and do funny things. A clamp on ammeter will be more accurate for doing this test. I've been told in the past anything under half an amp draw is normal, but I'm not a sparky. Keen to know other peoples thoughts.
I'd say you want something less than 100mA, 50mA would be even better. The only way I am aware of to accurately measure draw is to connect a battery maintainer set to 12.5v to the + post of the battery and to machine frame ground. Allow an hour or so for all the machine modules to go to sleep then disconnect the negative battery cable and connect an ammeter between the negative battery post and the negative cable.
Drawing only 5 milliamps per day will haul a battery down substantially in 30 days, but for it to go down substantially in 5 days takes 50 milliamps. I have tested many a vehicle through my Fluke 87 along with my Milliamp Clamp , and on single battery applications if machine is used only every couple weeks, it better be a tiny parasitic load. Simon C
Half an amp will kill a battery super fast but especially in the cold as the load does not change but the batteries capacity changes drastically. Simon C
Sounds like something that is Pulse Width Modulated. Check your diagram like Nige said, for anything that uses PWM, Hydraulic Pump Solenoids, Thumb wheel for Aux. Hydraulics, that gets its power from #10 Key switch.