fan problems!!! again!

[ctr kid]

ok here is the low down!

ive got a 4th gen prelude with jdm vtir conversion!
now on COLD start,
i turn the engine on, the fan wont start! which is good cos engine isnt hot enough!

2 seconds later i turn off the engine and the fan start!!! thats bs ... and wont turn off unless i disconect the battery, and then reconect!

my brother has the same prelude so i took a look at his! i switched the cooling fan relays but no luck still the same! i then took to it with the test light and found some results!

for some reason the frist prong top right on the relay holds power after u turn the key off and will continue to hold power untill u deconnect the battery! when testing my brothers car, the power would turn off when u back the key off!

ok if ur still with me ur a champ! so what determines the power 2 that relay???

[ECU-MAN]

I would just rewire it to run of the thermo fan switch.

[ctr kid]

i think its the fan controller??? do u know what that little black box next to the ecu is?
its got the word shindengen on it! it might b different in f22 and h22! i think my jdm conversion used the f22 one. but cant b sure!

[ECU-MAN]

ok
that black box near your ecu is the radiator control module
it should have 8 pins on it

ill give you the pin outs

pin 1 ( Yel ) goes to the relay in the under hood relay box ( coil side )
pin 2 (blk/yel) goes to the under dash fuesbox fuse 9 15A. should be live while the car is running.
pin 3 (yel/wht) goes to the condensor fan controlls
pin 4 ( blk ) ground ( 4ws right side of dash ) ( 2ws right kick pannel )
pin 5 (wht/yel) goes to engine coolant temp switch B ( switched to ground )
pin 6 (wht/grn) goes to under hood fues box. fuse 45 15A. condensor fan fuse
pin 7 (blk/yel) goes to the under dash srs fuse block. fuse 23. 15A
pin 8 (blu/red) goes to - condensor fan controlls. - goes to engine coolant temp switch A ( switched to ground ) - ECU


the under hood fuse 47 15A powers the fan relay always live. this then goes through the relay contacts to the thermo fan to ground.


good luck
hope this helps

[ctr kid]

woo hoo! lol.....happy happy joy joy
for some reason the yellow wire holds power that goes to the relay once ignition is off. in ur experiance what the hell let it continue power? ill send u $50 if u help me out! ...lol! im wondering, could the rad control mod b different in f22 and h22 cos im thinking the one in the car might b from the original f22 and not the vtec engine in it now!
my younger brother has a gen 4 f22 prelude just like mine! i swithed modules but no difference! and i noticed the yellow wire has no power when ignition is off on his prelude!

[ctr kid]

pin 8 (blu/red) goes to - condensor fan controlls

where is the condensor fan controlls???

[ECU-MAN]

I dont want your $$ dude, this is free info here.

what I would do is unplug that fan control unit . with the ignition off make sure you do not have 12v on pin 1 2 and 7. and that you do have power on pin 6

[ECU-MAN]

yel/wht goes to the coil side of the condensor fan relay

blu/red goes to the other side of the coil. but also to the ac/diode and ac thermo switch then ac switch

[ctr kid]

with the ignition off i have power at,
pin 6 (wht/grn) goes to under hood fues box. fuse 45 15A. condensor fan fuse
pin 1 ( Yel ) goes to the relay in the under hood relay box ( coil side )

dam it why 1? if i disconnect and reconnect batt, the yell wire power goes away!(thus stoping the fan!!!) my mission seems to b to stop power to yellow wire when ignition is off!
i wonder if this has anything 2 do with my ecu?

[ECU-MAN]

did you unplug the fan control unit whne you did this test


a simple option is to put a relay in series pin 1 so when the engine is off, pin 1 ( yel ) is open circuit and when the ign is on the relay is energised and compleated the circuit for normal opration.

however this will disable your ignition off fan run feature.

[ctr kid]

im not sure if this has anything to do with it but i noticed on my brothers prelude when ac is on and ignition is on(engine off) both fans run but not my car! also i dont have a sensore like au vtir in the end of top rad hose!block side

ok with the box unpluged!
ignition on
pin 2 (blk/yel) goes to the under dash fuesbox fuse 9 15A. should be live while the car is running
pin 5 (wht/yel) goes to engine coolant temp switch B ( switched to ground )
pin 6 (wht/grn) goes to under hood fues box. fuse 45 15A. condensor fan fuse
pin 7 (blk/yel) goes to the under dash srs fuse block. fuse 23. 15A
have power
ignition off
pin 6 (wht/grn) goes to under hood fues box. fuse 45 15A. condensor fan fuse

[ctr kid]

so from what u said... i relise that the black and yellow wires (2 of them no. 2 and 7) r getting power and they r not supost 2.

u fancy a holiday in brisbane ecu-man??? ...lol!

[ECU-MAN]

:)

Brisssy would be nice this time of year.

pin 2 and 7 are ment to have power when the ignition is on. thats normal.

if you can take a photo of your top hose to engine area.

also try your bro's ecu. see if there are any changes.

[ctr kid]

i just sold my brothers car yesterday!!! i did notice at the wreckers that an au spec vtir 94 model prelude has a sensor at the block on the top radiator hose!!! my jap spec does not have this.

atm im thinking that when i back off the key one of the contacts in the pig tail are not sending the reset signal to the radiator fan controller.. i think its one of the 2 blk/yel wires that lead in to the box

i got the idea after reading one of ur diy. exchange worn ignition contacts on prelude.... ur in everything!!! im gonna check it out today. ill let u know how i go!

[ctr kid]

i found the problem!
the jdm dont run a 'switch b' like f22 and h22 au. it was earthing out the relay and sending power to the fan!
switch b is what causes the fan to run up to 15mins after u turn the car off! it help cool the engine bay aswell as the water in the radiator! it will close when water temp is over 106 deg. the pin 5 (wht/yel) wire needed to be disconected!
as it was telling the module that the sensor is closed and the engine is hot!!

woo hoo!!! many thanks to ecu man!

[ECU-MAN]

awsome

glad you hear you solved the problem. good stuff