I have a 1995 Mustang Gt with 5.0L I have had a no start issue with no spark/occassional spark. I have replaced the coil, ignition module, PCM, distributor (remanned), igition switch, constant control relay module and still no spark. the wires are within spec . I have been going thru the checks on this website (http://easyautodiagnostics.com/ford_...d_module_5.php). got to Step 5 - I connect the test light to the signal wire and the + terminal on the battery, it lights up w/o the ignition being on (so that means there's a short right) . Key in run it goes out. I checked it with the coil connection unplugged and the circuit is broken, so I connected the test light to the Hot in run and Start side of the connector and test light lights up with the key in the off position. When I cut the key on, the light goes out.. When I hook the test light up to the - battery terminal, its the opposite, no light with key off and light when key in run. I checked the connection at the C104 connector and the short is between fuse and connector. Is there a short or is it supposed to be this way
I think I have an open circuit to ground in the Hot in Start or Run Circuit and I do not think there should be a grounded circuit with the key off . This circuit is Circuit 16 on the Ford wiring diagram. It Goes from the interior fuse 18 to the Coil positive then to the radio interference capacitor to the dizzy to the ICM and to the constant control relay module. If I probe this circuit at the C104 connector on pin 27 for the 16 circuit with a test light hooked to the positive terminal of the battery, it lights up indicating a completed circuit to ground. If I take the fuse #18 out and probe the circuit, it powers the CCRM and the relays start switching. I have continuity to all of these circuits, but I also have around 35 ohms (on a 200ohm scale). I am thinking I have a short between the C104 connector and the CCRM or a short between the connector and the fuse, but I can't think this out. What do you think.
This has been kicking my but for 8 weeks. Any help would be very appreciated.