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Hi speed cooling fan trouble

admir87

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are you getting the change in voltage at blue/white? and orange/blue, when you dissconnect the temp sensor and wait 12sec, plus 6sec

just checked my wiring diagram,

blue/white is signal from ecu
so with no highspeed fan on it should be at 13v
with high speed fan on it goes to -0.22v


and orange/blue is power to highspeed fan so basically,

no fan no voltage
highfan ON, 13v
 

Brett_jjj

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Theres no voltage change at all on the blue/white wire when measured at the relay terminal,or at the ecu.It is just constantly 5 volts.It has to be an ecu problem,yeah?.The wreckers where I am wants $150 for a second hand ecu.
 

admir87

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mate i think its the ecu, if theres 5v at both ends, its not giving the right signal, mine has 12v with fans off,

have you checked earths at ecu??

also the orange/blue wire, does it get any voltage after 20sec of the temp sensor been disconnected? also are you testing with engine ON?
 

Brett_jjj

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Ive tested it with the engine running.Ive also tested it with it ignition key in the on position,engine not running.It stays the same-5 volts.Will go recheck orange/blue wire to see if it gets voltage after 20 sec.
 

admir87

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20sec after disconnecting temp sensor?

with engine ON
 

Brett_jjj

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The orange/blue wire has 9 volts when the temp sensor wiring is disconnected and the engine is running,and the fan has switched on.It is on 0.06 volts(when first starting the engine),then when the fan starts, it goes up to 9 volts.
 

admir87

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so the high speed fan turned on??

if it did, i dont think you have a problem
 

Brett_jjj

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It didnt change speed,it is just staying the same,unless its starting straight up on hi.Before you could easily hear it going to the hi speed from lo,Id tested it heaps of times before by disconnecting the sensor wiring.The other day when I tested the fan straight to the battery,you can easily hear hi kick in when changing from low speed.This is doin my head in.It has got me stuffed what is going on with it.
 

admir87

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i dunno, i'd have to hear it myself....

what happens with the same test above, then while the fan is running you pull out the high speed relay, and do the same with just low speed relay disonnected, can you hear it drop speed?
 

Brett_jjj

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I dont know,the blue/white wire voltage is not right,the fan doesnt change speeds,but works fine when jumpered to battery,Hi fan commanded on with tech 1,does nothing,I jsut dont know,Im gonna have to try another ecu.I will go pull the hi relay while the fan is going.
 
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