I have a 1989 F-150 with a hidden electical short. The battry is drained if I leave it connected for 2 days or more and don't drive the truck. I found a similar question here, the response was to disconnect the spark box and see if the battery still went dead. OK, what is a spark box and where would I find it? Never heard of one before! Thanks, JB

HERE IS HOW TO CHECK FOR A BATTERY DRAIN. TURN OFF ALL SWITCHES, MAKE SURE THE GLOVE COMPARTMENT IS CLOSED & THAT THE LITE INSIDE IS GOING OUT .RAISE THE HOOD, DISABLE THE UNDER HOOD LIGHT. CLOSE ALL THE DOORS TIGHT. MAKE SURE ALL COURTESY LIGHTS ARE GOING OUT. GET A 12 VOLT CIRCUIT TESTER, { A SEE THROUGH ICEPICK WITH A LIGHT INSIDE }. REMOVE THE NEG BATTERY CABLE, PUT ONE END OF THE TESTER ON THE NEG BATTERY POST. PUT THE OTHER END OF THE TESTER ON A GOOD GROUND. IF THE TEST LIGHT LIGHTS UP THAT SAYS THERE IS A BATTERY DRAIN. IF THE LIGHT IS ON. START PULLING FUSES ONE AT A TIME FROM THE FUSE/ RELAY BOX NEAR THE BATTERY. WHEN THE LIGHT GOES OUT THAT IS THE DRAINING CIRCUIT. YOU MAY WANT TO DISCONNECT THE ALTERNATOR. ALTERNATORS CAN CHARGE THE BATTERY WHEN THE MOTOR IS RUNNING & IF SOMETHING IS WRONG INSIDE THEY CAN DRAIN THE BATTERY WHEN STOPPED OVERNIGHT.