Hello, I have been working on a electronic shifter for my AW4 transmission. There are 2 solenoids in the transmission, 12v has to be supplied to trigger them and they are grounded within the transmission. What I Have is an adruino uno with 2 inputs, Shift up and shift down. Then it has 2 outputs sol1 and sol2. I have the board programmed and i have tested it on my bread board with leds and it works for the led's at least. On my output i have then both running to a npn transistor then have it hooked to a relay on the board which is supposed to supply my 12v power. I am using 330ohm resistors between the base and the arduino pin. Im just getting very frustrated because everything on the breadboard works but when i try with the relays it freaks out and does not go through the code right it seems. the relays i have have a 5v coil if that means anything. Any ideas on whats going on?
Probably a hardware design fault. Have you got flyback diodes across the solenoids? If that isn't the problem, post a diagram of your circuit and perhaps somebody can see what's wrong.