F150 with a Draw

I have an 88 F150 that has power being drawn when the car is off. Have changed battery and alternator. How do I go about finding this draw has anyone ran into this before........ was also wondering could it be the starter or something smalll like a light ?

Also i had a kill switch on the Battery and it would still die if not driven every couple days

how old is the battery? have you had it tested?

most vehicles are constantly using power because they have electronics that don't switch off even when they're not running. have the battery checked, if it's fine then have the alterntor tested.

You can check for current draw with most multimeters, if you dont have one, you can get one adequate for this for less than 20$. Disconnect a battery cable(doesnt matter which one, current draw is the same on either, just makes a difference in how the meter leads connect) and connect the meter in line. You will see a draw somewhere between 250 and 750milliamps(1/4 to 3/4 amp) usually, some may be more or less. This draw is while the computer is powering up, it should drop back to almost 0 after a few seconds. If you have constant current draw, pull the fuses one at a time to find the circuit the draw is on, and proceed from there. Unhook any accessories(radio`s, amplifiers, radar detectors...ect) one at a time . Make sure no interior lights, or brake lights are staying on. The dome light alone will draw around 1 amp, but a good battery will still start the vehicle even after the dome light is left on all night. Most auto batteries are in the neighborhood of 60-80 amp hours. If your battery is going down even with a shut off switch, i suspect a bad battery. You said you changed the battery, was this a new one, or one that was sposed to be good??? You can also test for current draw with a test light inserted between the batt cable and battery, the more draw, the brighter the light will glow. But you wont know how much draw that is, i suggest getting a decent meter for troubleshooting. Have the battery tested first though. Charge it overnight with 6-10 amps, you cant properly test a battery until you at least try to charge it.