Code reader won't flash - Am i doing something wrong?
 

I built the homemade LED tester using schematics found here. I am testing an early (1991 300CE) M104 motor with the 16 pin socket beside the battery. No + in pin 16, but hooking to the positive battery cable, or to pin 3 gives me power - with the black plug in pin 2 (ground). The LED lights up - I put the 3rd wire in any of the open sockets and press the switch and hold it for 3-4 seconds. LED lights up, and stays lit when I let up on the switch, but no flashes.

No codes? Or is something wrong here? I thought, if there were no codes, I should get one flash -right?

ryan

Do you have the ignition turned on in the start position?

KOEO.