Actually to truly test you have to let it sit for over 4 hours. Thats how long it take for the climate control module to go to sleep.

From the eSI system..
"When diagnosing battery draws on trucks equipped with the automatic dual zone HVAC controls (RPO CJ2), technicians should keep in mind that the control head does not completely "go to sleep" until after 150-250 minutes, or up to 4-¼ hours, from when the ignition key is turned OFF. This is a normal condition. In these cases, DO NOT replace the control head."

Then they say this in another bulletin.
"Vehicle may have a concern with the battery going dead overnight. The draw can be from 40 to 60 mA. This is due to the HVAC control head staying "awake". Further diagnostics may show that the draw is reduced to approx 5 - 9 mA with either the front HVAC controller unplugged or HVAC fuse B pulled. Disconnecting (and reconnecting) the battery may result in the draw being gone until the next key cycle. The rear HVAC head is unrelated to this issue.

Recommendation/Instructions:
A draw of approx. 60 mA for 2.5 to 3 hours after vehicle shutdown is normal. The time varies with ambient temperature. However, this should NOT be enough to drain the battery. DO NOT replace the HVAC control head for a draw of 60 mA (approx) or less."

Attached is a pdf of the parasitic draw testing in the eSI system.

 

Thats a very useful document, thank you!

 

Sent you a PM Ocean....

 

Had the same exact issue in my 2004, well same exact scenario. Battery died a week before I bought (Carfax) then a couple weeks later then about 3 months after that. On the 3rd battery I researched. Hopefully its just as simple for you as it was for me and also my boss who's Corvette's battery died as often as mine. Pull the OnStar fuse. Apparently the Onstar constantly draws s charge. Its all I did and I'm on the same battery 5+ years now.

 

I have the same issue. Every fall/winter when the temp drops my battery cacks. I have replaced 4 batteries in the last 4 yrs. Once the battery dies. Its pooched. You can charge it and sometimes it will go into sulphication cycle or take the charge. Doesnt matter though because its going to die.

I also have a clifford alarm and only drive it once every week or two.

I also had the battery light sometimes stay on if i didnt turn the key back far enough before pulling key out. I have bought the electrical switch but havent installed it yet.

 

Thanks for posting

 

There was also a note in the eSI system regarding the ignition cylinder on battery rundown. Odds are you would notice other things though like not being able to crank or lights staying on.

"When diagnosing a concern regarding an intermittent vehicle no crank or dead battery, technicians should remove and reinstall the ignition switch using the Ignition Switch Replacement procedure in the Steering Wheel and Column section of SI. The ignition switch may have been misindexed in the steering column during a previous replacement.
If the ignition switch is misindexed in one direction, the ignition switch circuits will not be completely open when the ignition switch is in the OFF position with the key removed. This may result in lights remaining on or instrument panel lights illuminating, which will drain the battery. If the ignition switch is misindexed in the opposite direction, the ignition circuits will open correctly but the ignition switch may not close the crank circuit properly when the ignition key is turned to the crank position. This will result in a no crank concern."