I dont find a code 21 for the EATC here is a list of codes and how to run a self test to get codes
How to troubleshoot the (EATC) Electronic Automatic...
That's for a newer version of the EATC system. For the 1998-2000 Explorer (possibly 1995-1997 as well), this is the proper troubleshooting information. This is from
He did a conversion from manual to EATC in his Ranger using the Explorer EATC system. There is a very good description of the system and components. There are numerous threads around here that discuss EATC troubleshooting and installation. There are also many threads discussing manual-to-EATC conversions and EATC-to-manual conversions.
There's no error 21, but my guess would be a problem with the blend door actuator or wiring. Did you get the proper actuator for the EATC system?
From :
"Advanced self-test mode
The EATC has an advanced self-diagnostic test mode. A great description of it can be found here on the P71 interceptor site I mentioned previously. What he's posted is a direct "cut and paste" from the Ford service manual. I'll paraphrase here and add some additional codes you may see not mentioned in that document.
Basically, what you do is press and hold the OFF button on the head unit, then press FLOOR while still holding down OFF. Now quickly release both buttons and press the AUTOMATIC button.
At this point a little line will appear to rotate in the middle of the display. This indicates testing is in progress.
The test can take what seems to be a long while when you're waiting for it! Just let it run and don't worry.
At the end, the display will begin flashing numbers, or it will simply light up everything on the display and halt.
If only "888" appears for the number, and everything else on the display is lit up, then you have passed the advanced self-test! Congratulations! You can now proceed with the installation.
If there are numbers, write them down as they appear. Here's what they mean:
022, 024 - Blend door actuator shorted
025 - Blend door actuator not responding properly
030 - cabin temp sensor shorted (either wiring or bad sensor)
031 - cabin temp sensor not connected or failed (open circuit)
040, 042 - outside (ambient) sensor shorted (wiring or bad sensor)
041, 043 - outside (ambient) sensor not connected or failed (open circuit)
050, 052 - solar radiation sensor shorted
115, 125 - bad/no data from vehicle network (you'll get this always testing outside the vehicle)"
