wire size

I apologize if I'm testing your patience. I know enough to make it work, and want to learn and understand enough to make it last and take from this experience for future installs. What you said makes sense, the wire is coming from the battery and I'm tapping it prior to its connection point essentially the same as running a new feed from the battery. I just don't understand what happens when the constant power gets to the remote start controller. If it's fused with two lines combined up to max 60AMP's is the controller bearing the load of everything running while remote started? If not, why fuse it so high?

The answer to your last question is YES. But naturally there are exceptions, remember a top of the line manufacturer like compustar has to cover all possibilities. Generally a starter wire draws as little as 5 amps if it's relayed say under the hood (engine bay fuse box). British Fords in the 80s drew up to 30 amps on the then single ignition wire, one reason why modern cars have multiple ignitions. Whereas Mk l and Mk ll VW Golfs only drew about 5 amps on the ignition because it went straight to a fuse box with a thick battery fed constant and the various functions were relayed out. It also had an ignition ll. Also on nearly all vehicles except BMW and Porsche, on crank only ignition 1 and starter are powered. In practical terms run those fused wires to either the internal fuse box constant feed or the constant feed (s) at the ignition switch.

So in my case, the majority of the vehicle wiring is 24AWG. I'm assuming most of the power coming IN leaves back through the accessory wire? If this is the case, how does it not melt?

Sorry, you've completely lost me, maybe you should take this up with the alarm manufacturer. I've connected to the battery, ignition constant and main fascia fusebox feed over the years with never a problem.

And no it leaves through the ground wire.

I guess I'm just confused with what happens since we have all that power running into the controller to power devices through the two 12V constant lines. The 12V accessory and 12V ignition lines are both inline fused at 20 AMPs from the CompuStar harness. The vehicle wiring for both of these wires is 24AWG. Should I not reduce the fuse size?

NO! I don't want to take this daft thread any further but you are getting over involved in totally irrelevant minutia. The R/S manufacturer has to cater for differing wire sizes by different vehicle manufacturers. It's that simple. I'm involved in a tracker + immobiliser contract involving Toyota Prius, the wire we cut to immobilise the vehicle is on a 10 amp circuit and is equal to 28 ga wire. The immobiliser wires are 12 ga. It works, who cares.

Essentially that's the attitude I'm trying to avoid by asking these questions. I work in the mobile world as well on a fleet of over 1000 vehicles scattered throughout our province all fitted with aftermarket goodness - some built in house by our mechanics and others by joe contractor. I question why wires are melted, fuses blow, why solder joints fall apart, etc because I end up having to fix these things and want to prevent re-occurrences however my knowledge is limited so I ask questions so that I can learn. If the wires are undersized and the fuse is too high in most circumstances you're asking for trouble. This would never be acceptable in residential or commercial electrical systems. That's one thing that has always bothered me about the 12V world - lack of standards and code. Too many things are built to just "work". This was my first remote start install from scratch by myself so understanding exactly what is going on with the power and what direction it flows took me a bit but I'm pretty sure I have a firm grasp of what is going on thanks to your advice. We can leave things be.