Ok guys (and gals). Newbie here with an off the wall alarm system that I've modified, and having problems making it work.
Here's the deal. I have a 1957 Chevy and because of the 60 year old wiring that I don't trust, I've installed a Battery Brain Platinum battery cut-off system to completely disable the electrical system. However, I also wanted to add an alarm, and didn't want a keyless type, so I got a vintage ITEC alarm off of ebay. (See the original instructions and wiring diagram that came with the alarm below.)
Since I have the Battery Brain that completely disconnects the battery from the car, I can't use the original instructions, so I modified the wiring diagram a bit to bypass the cars electrical system (see the modified wiring diagram below the original instructions and diagram) and to add a key switch to turn it on and off. Basically, I have a separate horn relay that goes to the existing horns. "Grounding" door, trunk, hood alarm switches, and two "grounding" motion detectors (One under the hood and one inside the trunk). I also have a 12 volt light (rated at .1 amp, 1.2 watts) that I installed in the dash that turns on when the doors, hood or trunk is opened. This is the "voltage sensing" part of the system.
As far as I can tell, I have it wired up correctly, but it doesn't seem to work, so I must be missing something!
The original design sent 12 volts to the alarm through the red wire (shown attached to the cigarette lighter fuse, which is connected directly to the battery, so it always has 12 volts). The black wire is ground, the brown wire goes to the horn relay to activate the horns and the orange wire (shown attached to the "accessories" fuse, which only gets 12 volts when the ignition switch is turned to the "on" or "accessory" position) disables the alarm. If a voltage drop is detected through the red wire (i.e., open one of the doors, trunk, hood or jacking the car), this activates the alarm and makes the horns sound through the brown wire. However, if you open the doors, trunk, hood etc... then get in the car and put the ignition switch to "start" or "accessories", the orange wire now gets 12 volts and turns off the alarm (or keeps it from going off in the first place). If you get in the car and DON'T put the ignition switch to "start" or "accessories", the orange wire doesn't get 12 volts, so the alarm (after 10 seconds) sounds the horns. Am I correct so far?
Now, as you can see I've bypasses the entire car wiring and have the following connections:
The red 12V "power/sense" wire, which was originally connected to the cigarette lighter fuse on the fuse box, is now connected directly to the battery. (And since it's no longer going to the cigarette lighter fuse, I put a 2 amp fuse in-line "just in case".) The black "ground" wire IS connected to the chassis ground, so that hasn't changed. The brown "horn relay" wire is going to a separate horn relay that also has power going to it directly from the battery. When you ground the brown wire, it sends 12 volts from the battery to the horns and they blow. This part has been tested and works correctly. When the alarm "key switch" is in the "ON" position, 12 volts is sent to the dash light but the dash light doesn't "light" unless one of the doors, trunk, hood "pins" etc... is grounded. Should this happen, the circuit is complete and the dash light "lights". This causes the red "voltage sensor" wire to sense a drain on the battery and after 10 seconds, SHOULD sound the alarm, unless I turn the key switch to the "off" position. Once in the "off" position, the orange wire gets 12 volts and turns off the alarm. Here's where I'm getting stuck. With the key switch in the "on" position, and I open the doors, trunk, hood ect... it's NOT sounding the horns!
I've looked at my schematic until I'm blue in the face and can't figure out what I've done wrong. Can anyone out there help? Maybe my dash light isn't enough of a current draw for the alarm to sense??
Thanks
Ed


