You will need to do the Ignition Off Draw (IOD) test at the battery.
With no abnormal draw, alarm off, doors closed, time out circuits off (about 2 minutes)...you can still expect to see up to a 30 milliamp continuous draw which is normal. If you look at the amp-hr of the usual flooded lead-acid group 78 battery, you can see why the batteries often go dead in a couple of months if not driven or on a battery tender.
IF the drain is associated with the the harness coming of of that terminal, you should be able to detect it and measure it...and you might get lucky finding the culprit circuit pulling one fuse at a time from the fuse block. Had any fuses pop?
Also, there and at least half a dozen fusible links that come off of that terminal that you cannot disconnect...though you could likely disconnect the end user of such a circuit (such as PCM) and hope you pinpoint it.
There are other areas in the rear of the car that are independent of the front terminal.
By the way, if you are determined to start up front, take great care when you attempt to disconnect the that positive terminal's nut as they can be broken with too much force...an old warning from Viper Wizard Chuck Tator.
Do you have the 1996 red/black R/T 10 specific service manual?
One of my favorite questions involves the integrity of the OEM wiring. Specifically, has anyone added such things as stereo equipment, extra alarm, front or rear cameras,, wired in a cruise control, hard wired in a radar detector, attempted to wire in an alarm reset switch?? If any answer to those questions is "yes", look there first.
Also, headers can melt insulation on O2 sensors along with any nearby unshielded underwood wiring.
Disclaimer: I am not a tech or an engineer...just a hobbyist trying to keep our Vipers going. Also, my favorite Vipers are stock...followed by stock and stock.
P.S. I forgot to ask if there is an added on piggyback engine management system ??
The only add on I can see is the Pioneer stereo. I don't listen to radio when I drive so the face plate stays in the glove box and I removed the amps to make more room in the trunk.
Yes, I do have the 1996 RT/10 service manual.
I bought the car in 2014 and don't recall any issues the first 4 years. The last time I addressed this issue was 2018 and the old battery died. Never could figure it out. Went through a couple of batteries on warranty. and I've had the car on a battery tender since then. Last battery purchase was 4 years ago April 2019.
Until recently, the last time I drove the car was 2019 when I moved. Took it out a couple of weeks ago. No problem starting, though I am concerned about parking somewhere and coming out to a dead battery.
The car has 18716 miles on it. Since 2014 I've driven it 545 miles.
Not a fun task to tackle. Agree that you need to document the drain first...before you start the task of sorting source of said drain if found.
Aside from my own prejudices concerning add-on wiring misadventures, I would think that any and all stereo wiring connections may still be a good starting point.
One personal observation over the past 27 years of Viper ownership: the general run-of-the-mill flooded lead acid batteries SEEM to be of a lesser quality and of a decreased service life then they were 15-20 years ago. And, YES...I do keep Vipers on battery tenders...with close to 1.25 million Viper-tender-hours experience. I also admit that occasionally I have been bitten by a "silent tender failure" over the years...i.e. green light on tender, weak or dead battery in Viper.
I have solved much of my own concerns by switching to AGM batteries for the Vipers. Yes they are heavy and expensive BUT they perform well in our street driven Vipers...lasting 2 to 3 times longer than the conventional flooded lead acid type.
One final point...I never leave home in a Viper without a strong, fully charged booster pack. Carrying a small, lightweight lithium iron phosphate booster battery might give you some peace of mind...especially if you cannot document an abnormal draw.
I test my tenders periodically to make sure they are producing current. The tender I use for the Viper relatively new and has a cigarette lighter plug.
I was looking at solar powered tenders that I can plug in to the cigarette lighter opening when I park the car someplace. No lack of sunshine here in Phoenix.
You mentioning booster battery got me looking portable booster pack jump starters that are small enough to keep in the trunk. I've had them before, when they were a lot bigger, and didn't last very long.
We all have a different threshold for flirting with potential automotive issues such as being stranded...but, admittedly, mine is low. That said, I would be eyeing a group 78 AGM battery...preferably one with a retail outlet nearby and a 4 year fully exchangeable warranty. ONE such battery would be an Interstate MTZ. Best of luck !!