thewhitewarrior

the fans on my 94 sti dont come on, i have left it on tick over till the temp got to 120 degrees, and the fans never came on, why could this be, cheers phil.

joz8968

iTrader: (13)

Don't allow that to happen too much!


Can't you test the voltage at the power lead of the multiplugs to both therno switches?

If that checks out okay, then the thermo switches are shagged... or fans' motors.

thewhitewarrior

ill check them do you mean the multiplugs connecting the engine loom to the right of the engine bay, also where are both the thermo switches? i have checked the fans and they are ok, cheers phil.

joz8968

iTrader: (13)

I think the two multiplugs are attached to the fans cowling - one each dedicated to either fan. You can't miss them - big grey-white muti-connecters...

thewhitewarrior

so where are the thermo switches hidding then.

STI_Baly

iTrader: (23)

Or try running the fans direct first to ensure they work. Then test thermo and so forth.

Checked the fuse first though didn't you??

joz8968

iTrader: (13)

Well the fan side of the multi-connectors must be connected to the thermo switches ... but I couldn't tell you as I've never investigated where they are. Sorry.

thewhitewarrior

thanks, i did the running the power wires to the fans and they work ok, like a div though i havent checked the fuses, ha ha, ill check them but just in case its not a fuse, where are the thermo switches,
cheers phil.

joz8968

iTrader: (13)

Why is it we all forget fuses first! lol... Er, except for Baly, that is.

thewhitewarrior

aaaaaha ha ha im so stupid........

joz8968

iTrader: (13)

Fuses then?!!!

thewhitewarrior

ill check them when it stops snowing, i aint going out there for a bit, thanks for proving im daft, he he.

thewhitewarrior

just one more thing, if i remove the brown plug under the inlet manifold, the one that goes on the alloy pipe going to the top hose, the fans come on, what is this plug to.

STI_Baly

iTrader: (23)

Lol don't worry we all forget i do to, when we work on the damn things we tend to run around looking at everything bar them.

Only because i got my thinking head on today i mention it.

And if i remember correctly the fans are controlled by the ECU and without looking at a wiring diagram i couldn't really pin it out for you. You might even want to replace the coolant sensor - i have no resistance values for this which would assist you unfortunately (does your car idle ok if not this could be due to a fauly coolant sensor?)

STI_Baly

iTrader: (23)

Thats the coolant sensor....this sounds like the issue. Lol i had only mentioned it in the above post a few seconds ago.

STI_Baly

iTrader: (23)

Broken plug probably as the clips are a pain - check it all over and should work ok after sorting this out.

But just wanted to add as Joz said further up do not run your motor into silly temps as this could lead to engine probs.

Good Luck 3 posts in a line on 1 thread is more than enough for me for today lol

thewhitewarrior

the car idles very slightly up n down, so if the plug it removed and the fans work, its more than likely to be the brown coolant sensor that is shagged.

joz8968

iTrader: (13)

My memory's a bit sketchy... but I think that could be the coolant temp sensor (that the ECU reads) and, when not connected, the fans do stay on! I think!

widdows

sounds right ive just replaced mine as the fans were playing up, old one had a layer of crap built up on it.

STI_Baly

iTrader: (23)

Yep it is the coolant sensor Joz but i cannot remember if the fans stay off when removed or on.

Anyway heres the sensor on the x-over pipe.

thewhitewarrior

thankyou, thankyou BALY you've done more than enough,
right, so at least the plug is doing its job.
i know i keep asking but where oh where is the thermo sensor tucked away at, please tell me.

joz8968

iTrader: (13)

LOL, I'm far too slow!

Yes. Get you car up to temp i.e. middle of gauge. If after a while the gague starts to move upwards slowly (because the fans are obviously not coming on), then pull off the coolant temp sensor connector. If they now come on, then I'd say 100% coolant temp sensor needs replacing. This would also corroborate the fact that both fans aren't coming on (i.e. you wouldn't necessarily expect both fans' motors to fail at the same time!).

Also, I' was being thick earlier. As Baly has said, the ECU no doubt controls when the fans turn on via info from the CTS... And not from standalone, preset, therno switches in the rad! - how primaitive lol

thewhitewarrior

ha ha ha, we all get a bit daft for a moment from time to time, im glad its not just me,
so i guess ill never find the thermo sensor, ha ha.
we will put this to rest now, ill check the fuses, and get a new coolant sensor, as im pretty sure it will be one of them,
thankyou,thankyou,thankyou,thankyou,thankyou to you all for what im sure was a record breaking speed thread for replies.
have fun in the snow.

tonyrally

120 degrees your a brave man if it had been a rover u would have cut the cat off an weighed it in by now lol