Hello all , I have been trying to diagnose my 94 caravan . I have checked all fuses , changed all three fan relays ( low fan , high fan , fan ground ) . I even changed the ECU behind the battery . I heard that had worked for one forum user with fan problems . The AC clutch does not kick in either . The fan does run when voltage is applied . The clutch functions when voltage is applied . ALL fuses check good . Am I missing something ? I there another relay besides the three I can see ? Any advice will be appreciated .

"The AC clutch does not kick in either . The fan does run when voltage is applied . The clutch functions when voltage is applied."

Based on the quoted statements, the problem that you didn't state is apparently the cooling fans and the A/C are not coming on...correct?

Are they not coming on at all or just when you attempt to turn on the A/C? Your A/C clutch may not be engaging because of a low refrigerant charge. Have you had it checked? The fans won't turn on if the A/C doen't turn on. In the case of the fans not turning on when the temp rises, it appears you've checked everything but the coolant temperature sensor.

I'll try to be more clear . The cooling fan does not come on at all . I had read here that with the coolant temp sensor disconnected that turning the key to ON would start the fan . This is why I did not mention the sensor . Unplugging it takes it out of the loop . The fan doesn't run . In the case that some things I read on the Forum may not be true , or not true for my model year , I will replace the sensor and go from there . Concerning the AC Clutch , I have bypassed the pressure switch , a procedure that will make the clutch run on most anything that rolls down the road . No voltage to AC clutch . There is voltage to the AC Clutch FUSE in the underhood fuse pack .
Hope that makes things a bit clearer . If I ever figure it out , you can be sure I will post the FIX .