Originally posted by DigitalOutkast
where would the ground be i don't understand?
Both the wire from the parking light circuit and the one from the turn signal circuit should be grounded at rest. Use your DMM to test each wire. With the parking lights off, connect one lead of your DMM to a 12V+ source and the other lead to the + wire going to your parking lights. You should see 12V. Likewise, with your turn signals off, connect one lead to a 12V+ source and the other lead to the + going to your turn signal. You should see 12V. This means that both wires are grounded at rest. So, your side markers will flash under the following conditions:
parking lights off, turn signal off = side marker off
parking lights on, turn signal off = side marker on steady
parking lights off, turn signal on = side marker flashing in phase with turn signal
parking lights on, turn signal on = side marker flashing out of phase with turn signal (because the side marker will see two + when both lamps are on)
This is not the case for all cars. It works for many of the Honda/Acura cars I've done. Use your DMM to test for the ground at rest.