Frustrated Husbands stang.97 gt with 99 4.6..bare w/me trying to help hubby.the initial problem was the hose to temp sensor thats located on back,busted.replaced hose&sensor.never overheated but temp to high.so replaced thermostat.still to high.tested fan.runs with front temp sensor unpluged.replaced temp sensor&harness.still to high.water pump and radiator was replaced about a year ago.we have read about ccrm,is this our last resort?and if box is bad,wouldnt it effect fuel pump(replaced),clutch(replaced) and the other relays associated?cause those things are fine.ty in advanced for any advice
I have helped more than one person who THOUGHT they had an over heating problem that turned out to be electrical in nature. IE a poor ground CAUSING a false high temperature reading. In some cases people "part swapped" the complete fan control and cooling system before reaching out for help.
Recommendation. Don't load up the parts cannon in an attempt to "part swap" to a solution. Cover the basics first. Test as much as possible. Then repair.
To anyone else reading any of my posts I usually include the line: Today's cars simply will not run right without a strong battery and charging system! Cut corners here at your own risk I'm a big believer in starting with the basics. As such I...
Confirm that the cooling fan works on BOTH speeds. One method is to test by jumping the fan directly from battery power.
NOTE, the CCRM is multiple relays under one cover. It's quite possible for one relay to fail while the others work fine.
Hands down the easiest way to test this is with a bi-directional ODB2 scanner. With a bi-directional ODB2 scanner it's possible to "command" the various speed fans to run and then actually see what happens.
Even without bi-directional control just being able to see the various PID's such as ECT and called for fan speed are very helpful in trouble shooting.
Here's some information on an affordable Windows based unit. ForScan ODB2 scanner w ELM327 USB
While working on your car have you ever wanted: to find an ODB2 operational PID value (say fuel pressure or MAF)? How about graph a PID value over time? Or compare multiple PID's over time? Access a bi-directional PCM control such as test a...