new to board, been reading posts for a while, came over from camaroz28.com. I've got an 88 iroc 305 tpi. the right fan which is the cooling (correct me if i'm wrong) fan stays on with key on eng. off. the left fan comes on when the eng. is running. what's the issue? few notes, #1 i am a mechanic. a/c comp does not come on but not worried about it jumped the switch it works. low on freon. this car seems to run really cool considering the high temp charataristics of these cars, about 160 deg. unplugged the fp- fan fuse it stays running , unplug the relay and it shuts off. could i have a bad temp sensor? what do you guys think?

 

I believe the right side fan is the higher temp fan. Check the sensor on the right hand side head between the 6 and 8 cylinders. Unplug the connector and see if the fan stays off. It will also run with AC but I think both fans should run it there is a problem with that. Place to start anyway.

 

both fans do run when running, no matter what the temp. i will try your suggestion first and go from there. thanks anybody else have any ideas?

 

Also on the frame rail on right side on the AC high pressure line there is a fan switch. Not sure whether this is a NC or NO switch, they are different on various years, but it could be bad also.

 

not to be rude but, i am pretty good with a/c and I think my problem is not caused by the a/c. #1 the fan that stays on with the key on is the coolant fan, witch is the pass. side fan. # 2 the a/c is totally out of freon wich will keep the compressor and the a/c fan off at all times. this is why i am confused and think this is electrical. the coolant fan runs with the key on, but both fans come on when running which is what confuses me the a/c fan should not come on at all and the coolant fan should come on at a certain temp. do both of these fan run off the coolant temp switch and or sensor? i'm stuck.

 

The primary or driver side fan is ECM controlled, but will default to the on state if the aux or pass fan is forced on before the engine CTS temp sender calls for the primary fan. 2 things cause this, first either the wire from the aux fan sw on the pass side between cyl's 6&8 is shorted to ground and/or the switch itself is bad, or second the normally closed pressure sw in the AC is not closed. Many guys have this problem when they do the AC delete mod. In non AC models that sw is not there and the ECM term is tied to ground.