All you need to get codes out of the computer is a paper clip jumpered between the white/red wire (#48) and the black/white wire (#46). The white/red wire (#48) is a short pigtail off of the big connector.
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.
See
http://www.troublecodes.net/Ford/
OR
See
http://www.mustangworks.com/articles/electronics/eec-iv_codes.html
IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
For those who are intimidated by all the wires & connections, see
http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.
Or for a nicer scanner see
http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $35.
If you have all the wires identified and then jumper them and don't get any codes, then one of the wires is broken.
With the power off, measure the resistance between the black/white wire (#46) and battery ground. You should see less than 1.5 ohms, more than 1.5 ohms and you have a broken wire or bad connection.
At this point unless you have a DVM or multimeter and some electrical smarts, you need to find someone good with electrical circuits. It is very difficult to get someone enough training to troubleshoot electrical problems by way of Stangnet.
If you have the tools & electrical training I will be glad to help. If not, then this is going to be very difficult for you.
