Below is a diagram of the X13025 connector, taken from 8100.0-02 in the ETM. This is the connector on the car harness, which I'll mate with 61 13 1 378 138.
The pinout of the X13025 connector, found via several diagrams in the ETM:
| Pin # | Function |
| 1 | hot-at-all-times |
| 2 | ignition 12VDC |
| 3 | chassis ground |
| 4 | (-) driver's door trigger |
| 5 | (-) passenger's door |
| 6 | (-) rear door trigger (not applicable) |
| 7 | (+) siren |
| 8 | (-) parking lights |
| 9 | (+) lock (positive pulse) |
| 10 | (+) unlock (positive pulse) |
| 11 | (-) trunk trigger |
| 12 | supervised dome lighting? |
This gives us the basic triggers, power, lock and unlock, and parking light feedback. The siren pin presumably signals the harness for the alarm siren under the hood, which I should be able to use for the Stellar siren if that's what I choose to install (the alternative is to buy a factory one, P/N 65 73 9 416 245).
Hood Trigger
Connector X10244 in the ETM should be taped to the same area as connector X13025 (behind the glove box). It's a 1-pin black connector. This is the signal from both the hood switch and the radio anti-theft switch.

The ETM shows connector X371 as the hood switch connector. It has pin 1 connected to ground, and pin 2 wired to pin 1 in X10244. This trigger is in parallel to the radio anti-theft switch.

Foot Brake
Pin 2 on connector X78 (blue/red) should be wired to the black/white wire on the Stellar alarm. This will let the alarm lock the doors the first time the brake is depressed after the car is started.

Wiring Table
| Car Connector/Pin | Alarm Wire | Description |
| X13025 / 1 (red/yellow) | brown/blue | hot-at-all-times |
| X13025 / 2 (violet/white) | green | hot in accessory, run and start (ignition) |
| X13025 / 3 (brown/orange) | black | ground |
| X13025 / 4 (brown/green/yellow) | diode | driver's door trigger |
| X13025 / 5 (brown/blue/green) | diode | passenger's door trigger |
| X13025 / 6 | UNUSED | red jumper (single wire) |
| X13025 / 7 (black/blue) | white | siren |
| X13025 / 8 (blue/green/yellow) | orange (from relay output) | Parking lights |
| X13025 / 9 (green/white) | blue/white | + lock |
| X13025 / 10 (blue/red/yellow) | green/white | + unlock |
| X13025 / 11 (brown/white) | red jumper (2 wires) | trunk trigger |
| X13025 / 12 (white) | ??? | unused |
| X10244 (violet/green/yellow) | brown/yellow | hood trigger |
| X78 / 2 | black/white | foot brake |
The timing relay socket shipped today. I may or may not use the timing relay, but it'll be good to have around. I sort of like auto-locking the first time I hit the brake after starting the car, but don't want the windows to roll up in that case. So to do it the way I want will probably require more smarts (one of my microcontroller modules should work fine). The alarm can't be told to use a short pulse for auto-locking and a long pulse for arming; it always emits a lock pulse of the same length (can be set to either .5 seconds or 3.5 seconds). If I had to add another relay to get what I want with the timing relay, I might as well use one of my microcontroller modules; it'll take up less space, and I can make it do whatever I want here.
I tucked the alarm in place and zip-tied the mess of wires together, tucked in sort of neatly. I'll have to take it all out again to do the window rollup relay, but it's no big deal. I put the glovebox and underdash panel back in place. It's ready to be tested in the real world.
It looks like the warn-away signal for the Stellar 2-stage shock sensor is the white wire on its 4-pin connector. That would mean the blue wire is the second stage (full alarm). It looks like it pulls the voltage down when triggered, and that the alarm brain has a pull-up resistor to keep the signal at 5V when the sensor is not triggering.
In the harness I made for me existing motion sensor, the violet wire is ground (matched the old CompuStar alarm wiring), red is 12V, black/white is the first stage and white/gray is the second stage. Checking these, it looks like the outputs of the sensor float around .3V until triggered, at which point they pull voltage to ground. This may or may not work with the Stellar. Hopefully the .3V is just floating voltage.
So, I can splice into the 2-stage shock sensor wiring:
| Shock sensor wire | Motion sensor wire |
| black | violet |
| red | red |
| white | black/white |
| blue | white/gray |
Hmm, it seems as if the LED wire for the remote paging sensor is the green wire, it's the only one that oscillates when the alarm is armed. My meter shows it going from 5V to 3.3V or so, but that could just be the meter (display for DC is damped).
For now, I've wired only the valet button momentary contacts. I'm out of male tab disconnects, which I'd like to use for wiring in status LEDs. I put braided sleeve on the 4 wires for the Apem IP, and ran them under the center console. It's wired in to the valet button input on the alarm. I did not remove the center console to run the wires under the carpet; I've had my center console out 4 times, it's a lot of work. I'll do that the next time I have a real cause to remove my center console.
I installed the siren under the driver's headlight. There was already one hole in the aluminum, I drilled a second one. Right now the siren is just zip-tied in place, since I'm not sure I want to keep it in this location. But for now it will do. I wrapped the wiring with silicone splicing tape.
I am going to wire my motion sensor in parallel with the shock sensor. On the shock sensor, the red wire is power (12V) and the black wire is ground. The other two wires would be warn-away and full alarm signals. I don't yet know which is which, but it won't be hard to figure out.
I need to pick up some 5A fuses and some male disconnects from the hardware. I should also get some 30A fuses, since I'm almost out of them. Might as well pick up some fasteners for the siren too, in case I want to keep it where it is. The hole I drilled is 3/16" diameter.
I should also order a timed relay so I can get full window roll-up each time I lock with the alarm. The P&B CNT-35-26 from Mouser will work, though overkill.
For now, I shortened the main alarm harness by about 2 feet, and used some of the split loom to cover it. I don't have any 3/8" or 1/2" braided sleeve on hand. I soldered all of the wires I cut, and used heatshrink tubing to cover the joints. I also trimmed a mounting tab off of the alarm brain so it would fit in the factory location. It fits nicely.
I need to figure out what the extra wires are for, and how to wire up remote windows and convertible top. The manual doesn't cover the VTXC, only the VTX and VTXR. I sent email to Stellar, but don't expect a response since I know their support sucks. I need to document which wires are unused, then start checking them with the voltmeter.
The remote paging sensor has white foam tape on it. It'll look terrible on my windshield if I leave that on there. I have some black 3M VHB tape, but it's only .5" wide. I ordered some 2" diameter disks from McMaster-Carr, gray in color. We'll see how they look (I'm hoping it's a dark gray). The extended range antenna also has white foam tape on it. I'll replace that with the black VHB tape I have. Sigh, Stellar apparently buys tape at Wal-Mart.
I tested most of the alarm functions, it all seems to work fine. I wired the brake pedal wire, so I can use auto door lock control. I routed the wires for the extended range antenna and the remote paging sensor.
I need to fit everything in where I want it. The harnesses on the Stellar need to be shortened; they're long enough to cross the car, probably because they're the same ones used for their alarms with remote start. They also used big ugly split loom, which I'll replace with Halar braided sleeve.