Fans stay on ... HELP PLEASE!!!

[Guest]

heya i have a 96 legacy twin turbo ..

my fans are off until operating temperature and then the fans come on they stay on ..

car is not overheating and when the fans are on the engine cools down a little and make the heater go loop warm..

is there a seperate fan switch In these ? or is it operated by the coolant temperature sensor

any chances a relay isnt clicking off...

thanks for the help

[Joker]

Ecu controls Fans a AFAIK

so you are saying they dont turn off? check relay (I dont know where) someone may have more info than me...

[Guest]

 JoKer said:

Ecu controls Fans a AFAIK

so you are saying they dont turn off? check relay (I dont know where) someone may have more info than me...

yeah they stay on . both of them and dont switch off once it gets to operating temperature ... then engine starts loosing temp because they wont turn off .. maybe ill try a ECU reset ...

[Guest boostcut]

+1 on ecu reset. does your engine check light ever come on? does your car still have the same power as before this problem started

[Guest keltik]

Shitty fan relays?

[suubyduuby]

Faulty temp sensor? Are you getting a check engine light? If not, probably not a sensor issue.

Stuck relays could also be an issue. I would imagine they are mechanical and not solid-state. Have seen a lot of this at work - relays latching and not turning off. Creates all kinds of wonders! ;D

[suubyduuby]

Just to post further- a simple test would be to identify and remove the fan relays and bench test them. I would imagine they have 12V coils, so you should be able to test by hooking up the coil to 12V and make sure that the coil latches and then unlatches when power is removed.

[Guest]

Coolant temp sensor fault

You have code 21 in memory for sure.

Car will be hard to start cold unless you clear the code (which may not clear if the sensor is outside max parameters)

If code wont clear you need to replace the sensor first

If clear code works then, you still need to replace the sensor as it is about to fail forever

[Joker]

ok - +1 but where is said sensor (for the un initiated)

that bugger of a sensor copped tha blame (after i traded it in) for my Auto '90 GT for stalling! (rich as mofo)

[Guest]

It's fitting to the water manifold

Easy access to this after removing the alternator

[DRFVDR]

I remember back about 3 weeks to this exact same discussion

[Joker]

ta and only one way to learn is by doing! (i dont need to do this right now)

[Guest]

 DRFVDR said:

I remember back about 3 weeks to this exact same discussion

hrmm i done a search first .. couldnt find anything .. do you have a link?

[Guest]

today i changed the temperature sensor and replaced the relays the 4 black ones in a row in fuse box of engine bay... not sure if theres any others...

took for a drive .. and same problem grrrrr.

im out of ideas

[DRFVDR]

nah I dont have a link but it was a very very similiar discussion

thats a bugger that u done all that and still have same problem

could it be a thermostat fault ????

[Guest boostcut]

 crizpy said:

today i changed the temperature sensor and replaced the relays the 4 black ones in a row in fuse box of engine bay... not sure if theres any others...

took for a drive .. and same problem grrrrr.

im out of ideas

did you change the sender ? do they have a sender?or the sensor

[Guest]

 DRFVDR said:

nah I dont have a link but it was a very very similiar discussion

thats a bugger that u done all that and still have same problem

could it be a thermostat fault ????

i replaced the thermostat last week at that stage i hadnt realised the fans were staying on

[Guest]

 boostcut']

[quote name='crizpy said:

today i changed the temperature sensor and replaced the relays the 4 black ones in a row in fuse box of engine bay... not sure if theres any others...

took for a drive .. and same problem grrrrr.

im out of ideas

/quote]

did you change the sender ? do they have a sender?or the sensor

i changed the sensor and sender .. I used second hand parts But I highly doubt the other vehicle the parts were from had the same problem

[Guest boostcut]

hmmmm. try resetting computor.

[Guest keltik]

Do you have the air conditioning on or the green diagnostic plugs connected?

[Guest]

 keltik said:

Do you have the air conditioning on or the green diagnostic plugs connected?

Curious as to why you need AC on

Ahhh relaise now you think it may be in check mode, yes possible !

[Guest]

 crizpy said:

today i changed the temperature sensor and replaced the relays the 4 black ones in a row in fuse box of engine bay... not sure if theres any others...

took for a drive .. and same problem grrrrr.

im out of ideas

You must carry out clear memory so ECU will read new sensor properly

( at the moment the ecu is in a "safe" mode which need reset to clear other wise ecu goes on a standard temp of 50deg and runs fans continuously )

[Joker]

2nd fan is activated/utilised by "Climate Control" is it not? (or more often used etc)

[Guest]

Yes and No,

ECU get the A/C request and idles up and drives the fans as needed

Model dependant but normally one fan for engine temp control and both for A/C

[Joker]

brochure says "Climate Control" I am sure, not A/C (in its un-abbreviated form or otherwise)

[me=JoKer]be's anally pedantic[/me]

then thinks about above statement, the A/C is part of the Climate Control Unit which would be the only circuit to call for extra fan to be initialised