clifford amp draw older mercedes

I have some questions that I would appreciate input on from the seasoned auto alarm experts here. I realize that in the end I'll have to do more digging than I have to get to the bottom of things. My responsibility.
I own a 1991 Mercedes-Benz 300-SEL W126 model car purchased used in 1997 from an independent dealer who is no longer around. At the Mercedes factory an immobilizer of some sort was built in that's beneath the floor on the passenger side. Someone added a Clifford alarm(model unknown at this time). I believe the Clifford alarm is also down in that same area. Car can be locked/unlocked with a remote.
For some time the cars battery has been depleting quickly. I've traced it to the alarm system using the amp circuit on a voltage OHM meter.
I went from fuse to fuse to read the draw and saw the meter vascillating - suspected that was the alarm initializing. This circuit also controls the radio and others. Another circuit read a bit higher than I might consider normal - > .050mA. I pulled both these fuses as neither interfered with operation of the car - it would start with these 2 fuses removed. The battery contined to drop after removing fuses. Amp readings at all other fuses were basically zilch.
There is a red cable attached to the positive terminal of the cars battery. Fairly heavy gauge in my opinion. It leads down into the firewall and into the interior. I decided to change up my amp draw test by connecting one end of the VOM to the car battery ground strap(removed from battery) and the other to the batterys ground post. When I disconnected the red cable from the batteries postive post, the amp reading dropped like a rock. The cars turns signals no longer flash and horn no longer sounds once the batteries negative cable is reconnected. Pulling this red cable apparently killed the "alarm" portion of the Clifford system.
I was surprised a bit when the car started with this red cable removed from the batteries positive post. Apparently it's not tied to the ignition circuit. Whoever installed this alarm also installed a toggle swicth under the drivers side front panel. Flip it and on the next attempt to restart, the car will not start. OK - a kill switch. Why? I have no idea.
I know I'll need to get the flooring out on the passenger side to follow the red cable I've removed, but am wondering what part of this system could be causing such a large amp draw and is this part what commonly causes alarms to drain batteries. Don't mean to sound like I'm ragging on car alarms, but this one has been painful. My plan is to completely remove this alarm and get back to the original factory configuration. I'll have to figure that out.
Sorry for the rant and thanks for your time.

Caveat we're talking about a 20 year old product here.
Having said that I suspect that there's something else on the end of that battery lead, amp? inverter?
When new (note new) with the LED early Clifford drew about 35 milliamps.
I suggest you find out exactly what's on the end of that red wire.
Early Cliffords needed 5 amps for alarm and siren, 10-20 to run lights indicators and were directly connected to the battery, both POS and NEG.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Howie II:

No connection on negative battery post other than the ground strap.

There is an amp in the trunk, so what you've said makes sense. May be why the car starts with this red lead removed from the batteries positive post. As eluded to in the opening post the gauge of that red wire looks to be in the 8GA - 10GA range.

I can easily test this by turning on the radio. If I have no amplified sound with red cable off, I found my problem. I'll either live it that way or look into a relay that only allows power thru the red cable when the car is running.

I thank you for your time sir.

Treat the amp as a relay, it should get a trigger wire from the radio, usually blue or blue/white.
If it's permanently triggered i.e. always on that's your answer.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Howie II;

Thanks again - may be a few days before I can get back to this. Once resolved, I'll update the thread so that others may learn.