wayne613

Thanks! Always happy to throw in my laser-screwdriver...If I think I can give an answer with anything of substance.

cleteryan

Ok, from the diagrams the 2 power pins are #35 & #36 of the body harness connector. The grounds are #47,48,49,50. Connecting #36 to each of the grounds and the negative battery post I get a reading maxing out my volt meter both for continuity and voltage. But testing #35 I get no reading to any of the grounds or battery post with the key in the off and start positions.

wayne613

You are testing continuity from the battery negative terminal to the ground pins on the PCM, yes? If they all show near 0/beep, then grounds are good.

What does maxing out mean? Just that you get near same 12.x that you get from the battery terminals?

If 35 isn't getting squat, then trace it back to the fuse and/or relay first. I would also test continuity on that line between it and a ground, to check for a short, but from what you state, you already did that(but mentioning it just in case).
From http://iihs.net/fsm/?dir=39&viewfile...%20Mustang.pdf (page 5):
So that should have constant 12v (VBAT = battery voltage) power at all times...only a few reasons why it wouldn't...

wayne613

Looking at page 3 of http://iihs.net/fsm/?dir=40&viewfile...20-%204.6L.pdf , they share the same fuse, the lines just split off the BEC fuse, so there's something wrong with that particular line. Broken, burned through, corroded, snapped, or yanked out.

Both 35 and 36 are Grey with an orange stripe tied to fuse 42(15amp) in the BEC.

Keep in mind, if you can't find a break, and it looks a bit melted, it might have been a failure of your old PCM's circuit tied to that particular wire that caused the damage to begin with. So be cautious once you repair/temporarily jump that wire. Checking to see if it heats up in the first 10seconds. More likely corrosion or a break due to a rodent or the like, but it's possible.

cleteryan

I took the car to my regular mechanic and he could not find the problem, but thought it was an anti-theft problem so he sent me to the dealer. So I broke down and took the car to the dealer and they said the starter relay was not making good contact along with a vague wiring problem that they fixed. I asked for more details but they gave me the run around saying they would have to get the technician and he was at lunch so maybe I could check back later. It only ended up costing me $200 so obviously it was not a big problem. It is running good now!. Thanks again for all your help.

wayne613

Starter relay ain't tied to that...But glad to hear you got it fixed anyhow..

Likely you just got charged the 2hrs of labor for him to isolate the wiring issue after replacing the relay and related fuses did jack. *shrug*