****Please help my friend****

yep, pull the codes to see if they are stored in the KAM.

low coolant light is somewhat common. many have luck removing the sensor and cleaning it (it likely will have lots of crud built up on it).

good luck to him; good on ya' for helping him out.

Autozone will usually pull the codes for free. It's not difficult to do. Go to WalMart. Spend $23 bucks on a scanner for the Ford. THe diagnostic plug is part of the wiring harness behind the driver's side strut tower. The scanner plugs into it. The scanner comes with a very detailed instruction booklet that will tell you what to do.

The O2 sensors acting up can cause the CEL to go on and off at different times. But don't run with that - diagnose the problem; don't guess at it. The codes will help you do that.

Dump the codes and see what the computer says is wrong…

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.dalidesign.com/hbook/eectest.html for more descriptive help
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 Wal