7.3L Power Stroke Engine and DrivetrainDiscussion of the 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.
Batteries dies overnight. Hooked up charger, found heater fan running and vac. pump running. Ignition off, key out. Can turn off fan with switch. Something must be stuck somewhere, but what??? Please help. Thanks. 99 F350 7.3 diesel.
Sounds like you have a problem with your ignition switch.
The Heater fan relay control circuit gets it's power thru Fuse 22 which is fed by the Grey/yellow wire from the ignition switch.
The Vacuum pump is powered thru Fuse 28 which is fed by the Red/Black wire from the ignition switch.
Both these circuits should only be hot in run, but the individual switch contacts may not be interrupting the circuits when you turn the key off. both those fuses are under the instrument panel. If you pull the fuse and probe the socket with a voltmeter both sides should be dead when the key is off. If you find voltage on the hot side of the fuse with the key off, then move upstream to the ignition switch and test there.
Till I find the problem, I am shutting off the fan. Checked and found only 0.16 amp draw with fan shut off. At 7PM, the daylight running lights went on by themselves, with truck shut off for last hour. Now had to pull fuse for them to keep from draining batteries over night. Weird???? Still think it's the ignition switch???
Till I find the problem, I am shutting off the fan. Checked and found only 0.16 amp draw with fan shut off. At 7PM, the daylight running lights went on by themselves, with truck shut off for last hour. Now had to pull fuse for them to keep from draining batteries over night. Weird???? Still think it's the ignition switch???
Like I said in another fourm check your cab lights, mine were leaking and getting the GEM wet and haveing all the same problems as yours. Sealed my cab lights and solver all my problems!!!!!!!!!!!!!!!!!!!!!!!!!
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99 F350 4X4 DRW LB CC 7.3 Powerstroke Centurion
92 34.5ft NUWA 4 Season 5th Wheel
Had Truck With After Market Radio And Had Some Gauges In It. Someone Had Ran A 12volt Wire To Fuse Block And It Was Back Feeding Thru The Radio Some How. It Was Doing The Same Thing Park Lights Staying On And All. Try Putting Switch In Off Position Cut Headlights On And Then See If Ac/heat Blower Comes On. If So Then Thats The Same Problem I Had.
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