My sons '97 Mustang Gt keeps blowing the fuse for the computer, I was told this meant the computer was bad, but it still does it with a new computer. Any thoughts what is causing it?

 

What fuse number is blowing?

 

Not sure of the number, it is the ecc fuse. Just found out the battery is bad? Idk if that is what is doing it?

 

A bad battery is not going to cause that fuse to pop. You need to get a wiring diagram and start looking for everything that is on that fuse.

 

Do you have a manual for it?

 

No, we don't have a manual for it.

 

I believe that you can go to autozone.com, and access repair manuals through their website. (alldata?)

 

Found the book, it says that the Powertrain control module and the Constant control relay module are the only things on this fuse. I don't have a clue what those are or where they are???

 

The Powertrain control module is the "computer" that you've already replaced.

You SHOULD be able to find the "constant control relay module" in the electrical section of the manual.... (I don't know either. )

 

Terry, since you're the tech smartypants, will you post a link to this in our jackassery thread? Maybe Alan will see it and have a solution. My first thought was a wire shorting to ground. A wiggle test might be in order once the routing of the wires from the panel to the components is figured out.

 

The owners manual will not list everything on that circuit. You will have to study the wiring diagrams to see what else is powered by that fuse.

 

Not sure about the '97's but 2000 and up have a small black box under the dash by the steering column. It's full of relays and the dinger for seat belts and such. If one of the relays hangs up or shorts out (pretty common) it can cause all kinds of strange problems. It took me two days to find a parasitic drain on an '02 Mustang. Turns out it was the relay box. It's also considered a body control module. I would try to unplug it and see if it starts.

 

It is a 20A fuse labelled EEC?

If so that goes to the CCRM Connector 192 pin 10 and pin 8 and also the PCM Connector 294 pin 55.

At the CCRM pins 8 and 10 look like they are connected to the PCM power relay.


Does the fuse blow as soon as you turn the key to on?

 

Yes, that's the fuse, it blows as soon as the key is turned on. Before we replaced the pcm the fuel pump wouldn't even come on but the motor would crank. Now the fuel pump kicks on until the fuse blows then shuts off again and the motor cranks. I found the ccrm it is inside the fender apron. Pain to get to, will have to wait for the money to get a replacement and go from there.

 

Don't shotgun parts at it. Try unplugging the CCRM and see what happens when you turn the key on. You need to determine if it is an issue with a device or with the field wiring.