⚡ Do you want to be a successful electrician? Check out my complete training. Click here ???????? https://www.eunaupmotors.com.br/eletr... --------------------------------------------------------------------------------------- Brazil is a world leader in the development of automotive alarms, unfortunately what motivated this was the demand for vehicle protection due to theft, but in the end it is still a merit in the area. Over time, the automotive alarm has ceased to be just a protection system with an audible warning when tampered with, now the modern automotive alarm has many other functions that make the life of the car user easier and bring more convenience such as the visual signal on the turn signals, automatic locking of the doors, raising of the windows, turning off the radio, warning when you forget to turn off the flashlight, among others that may vary depending on the brand of the alarm. Most of these functions are activated directly by the alarm control according to the user's interest. Without a doubt, this is a great development that has been successful in Brazil, not only because of the need to protect the car, but also because of the possibility of automating windows, locks, headlights and sound systems, since here we still have many cars that leave the factory without these standard items. Today we are going to talk specifically about the FKS 902 Plus alarm that I installed in a 2002 Fiat Doblô. This one already had an old alarm installed, but the control was bad and the sensors were no longer working properly, so I decided to change it. I always like to start the installation with the siren, because it is the component that requires the most manual labor outside the car. In this case, I installed it on the firewall, because there is an original screw on the car's bodywork there. At the same time that I secured the siren with a 6mm nut, I also installed an eyelet terminal for grounding. Then I ran the wire to the fuse box where I will leave the alarm control unit. Still with the goal of installing the things that require the most movement and manual labor first, but now inside the car I installed the ultrasound sensors that are glued to the windshield with double-sided tape and about 10 cm below the upper part of the windshield. The wires can be passed over the windshield or under the dashboard, I prefer above the windshield and when lowering the left column the 2 wires go together to the alarm control unit. Then I started connecting the wires, in this specific case I already had an alarm installed and its wiring was in a sorry state with all the wires messed up so it gave me a little more work. I connected one wire at a time starting with the positive, negative and post-key power supplies, then the turn signal or blinker wires, then the fuel pump cut-off wires and the interface signal. All of these connection points must be carefully checked and we should never connect the wire from the new alarm to the end of a wire from the old alarm. We should always go to the point where the wire from the old alarm is connected and open the splice and redo it, because we will never know the quality of the splice until we open it. I connected all of these wires without any major difficulties, seeing the colors of each wire in the manual that comes with the new alarm and testing the signal compatible with each wire from the old alarm. However, I discovered that the wire for the open door sensor was not connected to the old alarm. I identified the wire and when I turned it on I noticed that the alarm always indicated that the door was open, even when it was closed. When testing with the test pen I noticed that even with the door closed there was still a very weak negative signal on the wire, but it was enough to inform the alarm that a door was open. I discovered that when I disconnect the connector that sends the signal from the door switch to the fuse box, the negative signal return disappears. To solve this problem, I installed a small common diode in series with the wire and connected the alarm wire after the diode. This worked perfectly because the negative signal return was eliminated by the diode. Another extra thing I did when installing this new alarm was to open the trunk. To do this, I used the alarm's auxiliary output 2, which is activated by the control's auxiliary button using a key with the letter (A). However, the alarm output sends a negative signal and the trunk device needs a positive signal, so I needed to install a conversion relay to solve this. In the end, it worked perfectly. After connecting all the wires, I tested the alarm and all its functions and realized that everything worked well. Thank you for following me this far in this alarm installation and I look forward to seeing you with our next topic. Thanks.