I want to start by thanking everyone here for helping so much, without you guys this would not be possible.
So I have an Arduino Pro connected to a Parallax RFID card reader.
12v to 5v regulator for the Arduino Pro and Parallax Reader.
Arduino Pro Pin 2 connects to the /Enable on the Reader.
Arduino Pin 8 connects to the TX on the Reader.
Arduino Pin 5 connects to 130Ohm resistor then to a Transistor.
Transistor connects to 30 amp Relay Switch with a Rectifier Diode across the coil on the relay. Cathode towards 12v+ and Anode towards 12v-.
The RFID reader basically works as a switch to control 2 other Relays: Fan Relay and Fuel Pump Relay (Both of these relays do NOT have diodes on them)
The set-up I have will work correctly most of the time, but 25% of the time it will switch on normally and then the relay will switch back off on its own without the RFID card being present.
Also when I turn on all three switches for the: Ignition, Fuel Pump, and Fans and then immediately turn off the Fuel Pump and Fan switches at the same time, the Ignition will turn off with them 75% of the time.
Video of problems:
(Watch in 720p HD for better quality)
I don’t think it is the code but if you want to look it over you are more than welcome:
Is the diode too large/ small and causing it to do this? Industrial Rectifier (NTE5804)
PRV - 400V Max IFSM - 200A Max
IF - 3A Max VF - 1.2V @ 3A
Is it the fact that the other 2 relays do not have diodes on them?
Here is a schematic sketch with an example of one of the switches for the “fans”.