"Phantom" Parasitic Draw.

[88lowrider]

Not sure if anyone is going to jump in on this or not as, I have been here before with this issue.

Mine is a 1988 GMC 1500 SLE Sierra that I made the low rider out of.
Electric windows, door locks.
350 V8 EFI, automatic trans.
Air, Power brakes, steering etc.

This is not a New problem. Been fighting this now since maybe the year 2000.
Park the truck on a Friday night after work, go to start it Monday Morning, Rrrr Rrrr, click click click, but Not Dead dead. Between 9 to 10 volts.

I let it set a Week, same thing, 9 to 10 volts but Never dead dead. Something is smart enough to shut down once it sees the battery is down to the 9 to 10 volts.

So, within 72 hrs (?) it will draw down the battery. Jump it, its fine driving and parking just over night.

I had put on a boat battery switch to the negative post to the battery and just kept turning it off if I had to let it set for more than a couple of days. (at that point, I was living Off the Grid, but now living On the Grid, I put on a small 1.2amp float charger now)

Over the years, since this problem started, no change in phantom draw:
Replaced starter.
Replaced Alt (2)
Replaced Battery (every two to three years)
Replaced brake light switch.
Replaced Computer.
Replaced heater control and door motor.
I know I am forgetting things too.
Checked grounds, checked wiring plugs and the list goes on.

Now new. The float charger has been holding it as I only drive the truck maybe once or twice a week. This time the truck sat for at least a week, maybe 20 days, down to 8 volts, 1.2 float charger was not able to hold it.

Charged the battery, checked the draw (stereo has been changed out too) and there she is reading .002 amps.....

I even read one time someone found it in the Instrument Cluster. Found some fellow in the mid west that rebuilds them and tests them for $150 bucks. Used on Ebay, they want around $120 to $150 used.. I might give that a try but just can't see were that could pull enough amps :-/

OH, and a Fellow gave me a Circuit design (that I can't find on line or I had printed it out) that I was able to put it on the battery or between the battery that would trigger a small relay that I could run it though a drop cord into the house and next to my bed as to Hear when the draw went above a Amp. I never got that built but my thinking now, I need to have it Drawing the amps and Then get out and start jerking fuses out until the alarm goes out.

Anyone know of a device or have a diagram on how to build something like that?

Something will come on and draw enough amps to pull the battery down.
Anyone want to take a stab at this, please ?