I am trying to set up fan control with no success. I can get the signal from the ecu (ground signal tested with ohm meter). I just cant get the fan to turn on. I used this diagram for my wiring of the fan. I use the setting in off Arron write up. The question is should I see 12v on js0 or ground. Right now I can only get it to ground nothing else. I tried differents transitor still nothing. Right now I am using ztx689 but I did try 2n2222a with same results. Any pointer on what to check would be very helpful. THANKS

 

JS0 should toggle to 5V when the fan is set to activate.

I don't know how much base current a ZTX689 needs to conduct but it may be past what the processor can supply. The 2N3904 or 2N2222A are ideal small switching transistors as they require little in the way of base current.

 

i cannot get it to put out 5v just ground only. I just read on dyi autotune that there is no need for the circuit on ms2 v2.3 or higher.
http://www.diyautotune.com/tech_arti...ifications.htm