Thermo fans ok?
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
Thermo fans ok?
Hi my car was sitting for 15mins idling, then it just turns off! does ecu have some sort of protection for the engine!?
I am pretty sure the fans aren't coming on! temp got to 120C!
How can i check that the fans are working and what to do about making sure they come on when needed, relays? do they stuff up?
thanks
I am pretty sure the fans aren't coming on! temp got to 120C!
How can i check that the fans are working and what to do about making sure they come on when needed, relays? do they stuff up?
thanks
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
Hi my car was sitting for 15mins idling, then it just turns off! does ecu have some sort of protection for the engine!?
I am pretty sure the fans aren't coming on! temp got to 120C!
How can i check that the fans are working and what to do about making sure they come on when needed, relays? do they stuff up?
thanks
I am pretty sure the fans aren't coming on! temp got to 120C!
How can i check that the fans are working and what to do about making sure they come on when needed, relays? do they stuff up?
thanks
Let the car sit running until temp hits 226*F, fans should come on. If not, trouble shoot the fans by testing fans, relay, wiring, etc.
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
Thanks for the info!
I tested the fans and they both work when power is applied!
Turning on A/C doesn't turn on any fan!
I still have to test the relay itself!
What tells the relay to work?
thanks
I tested the fans and they both work when power is applied!
Turning on A/C doesn't turn on any fan!
I still have to test the relay itself!
What tells the relay to work?
thanks
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
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Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
Hmmm ok checked the sensor at front on engine under tb, is that just for gauge! anyway it is very oily and sludgy around that area! but seems to be ok(connection anyway)
Looked at manual and it says the the CTS is near the oil dipstick! found the sensor and it is only a single slide on female end! it says to earth this and it will start the fans! well it didn't!
Unless manual is wrong and the two sensors are opposite, in that case i apologise to Rodj as you were right!
But i did the ACDL test ground, AB and both fans worked!
so does this mean that ecu is stuffed or that wire is shorting, i have a switch inside that i reckon the previous owner put in to take control of the fans(guessing) and is now stuffing them up!
Any other test to check system is ok?
i also ground AG and no codes stored! but on the lcd it has Service engine soon!
Looked at manual and it says the the CTS is near the oil dipstick! found the sensor and it is only a single slide on female end! it says to earth this and it will start the fans! well it didn't!
Unless manual is wrong and the two sensors are opposite, in that case i apologise to Rodj as you were right!
But i did the ACDL test ground, AB and both fans worked!
so does this mean that ecu is stuffed or that wire is shorting, i have a switch inside that i reckon the previous owner put in to take control of the fans(guessing) and is now stuffing them up!
Any other test to check system is ok?
i also ground AG and no codes stored! but on the lcd it has Service engine soon!
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
120c is 248f. That's a little hot ! I'd try not to let it get that hot again.
The fan relay is on the driver side inner wheel well housing adjacent to the battery. The fan relay is only $17.
http://www.ecklers.com/corvette-engi...1988-1994.html
The fan relay is on the driver side inner wheel well housing adjacent to the battery. The fan relay is only $17.
http://www.ecklers.com/corvette-engi...1988-1994.html
Last edited by pmihaltian; Jul 24, 2010 at 04:34 AM.
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
Yeah i won't be letting it get that hot again! i had it running while i was working on another car, so didn't see the temp the first time, assumed it was battery related! second time i saw the gauge and was not happy, thinking fans were working!
With respect to the fan relays, mine are on the side of the radiator cover, there are two as i have two thermos 1990 vette! but they are working! as fans operate when i ground pin B with A on the ACDL under s/wheel!
Maybe i will just change the cts under tb!
With respect to the fan relays, mine are on the side of the radiator cover, there are two as i have two thermos 1990 vette! but they are working! as fans operate when i ground pin B with A on the ACDL under s/wheel!
Maybe i will just change the cts under tb!
Pro
Joined: May 2006
Posts: 637
Likes: 0
Is your AC working correctly?
Try again starting the car with AC off, let it idle up to temp and see if the fans come on at 108/109 C.
Wich gauge did you look at, the digital one?
Does your SES light come on at ignition and go off when started?
You can also disconnect the TPS connector at the TB when started and wait a while to see if the SES light comes on then, it will set a code 22, that way you know if the ECM responds to the various sensors and is OK.
Just some free testing.
Try again starting the car with AC off, let it idle up to temp and see if the fans come on at 108/109 C.
Wich gauge did you look at, the digital one?
Does your SES light come on at ignition and go off when started?
You can also disconnect the TPS connector at the TB when started and wait a while to see if the SES light comes on then, it will set a code 22, that way you know if the ECM responds to the various sensors and is OK.
Just some free testing.
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
Is your AC working correctly?
When i switch it on i don't get any noise or click etc that normally a/c makes when on, definately not cold, i just thought it needed gas!
Light comes on AUTO and fan blows air, that is it.
Try again starting the car with AC off, let it idle up to temp and see if the fans come on at 108/109 C.
3 times now car goes over 120 then turns off!
Wich gauge did you look at, the digital one?
Analogue!
Does your SES light come on at ignition and go off when started?
Umm at one time it was on for a while, don't think it's on last time!
But my service ABS comes on! that doesn't work either!
You can also disconnect the TPS connector at the TB when started and wait a while to see if the SES light comes on then, it will set a code 22, that way you know if the ECM responds to the various sensors and is OK.
Will give it a go!
Just some free testing.
Thanks
When i switch it on i don't get any noise or click etc that normally a/c makes when on, definately not cold, i just thought it needed gas!
Light comes on AUTO and fan blows air, that is it.
Try again starting the car with AC off, let it idle up to temp and see if the fans come on at 108/109 C.
3 times now car goes over 120 then turns off!
Wich gauge did you look at, the digital one?
Analogue!
Does your SES light come on at ignition and go off when started?
Umm at one time it was on for a while, don't think it's on last time!
But my service ABS comes on! that doesn't work either!
You can also disconnect the TPS connector at the TB when started and wait a while to see if the SES light comes on then, it will set a code 22, that way you know if the ECM responds to the various sensors and is OK.
Will give it a go!
Just some free testing.
Thanks
Pro
Joined: May 2006
Posts: 637
Likes: 0
Take a small paperclip and bend it into a U (kind of), when sitting in the car, under the instrument panel, just above your knee there is a connector with 12 female pins.
Ignition off.
Connect the U shaped paperclip to the two upper right pins (from left to right on the upper row they are called F-E-D-C-B-A).
Turn on ignition but do not start, If everything works like it should, your fan(s) should come on now.
Either way, the SES light should start to blink now, short blinks followed by long blinks.
12 (one short followed by two long ones) allways comes first and is not a failure code, every code is shown three times in a row so you have time to write them down.
See what you come up with.
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
Have you tried to read the codes?
Take a small paperclip and bend it into a U (kind of), when sitting in the car, under the instrument panel, just above your knee there is a connector with 12 female pins.
Ignition off.
Connect the U shaped paperclip to the two upper right pins (from left to right on the upper row they are called F-E-D-C-B-A).
Turn on ignition but do not start, If everything works like it should, your fan(s) should come on now.
Either way, the SES light should start to blink now, short blinks followed by long blinks.
12 (one short followed by two long ones) allways comes first and is not a failure code, every code is shown three times in a row so you have time to write them down.
See what you come up with.
Take a small paperclip and bend it into a U (kind of), when sitting in the car, under the instrument panel, just above your knee there is a connector with 12 female pins.
Ignition off.
Connect the U shaped paperclip to the two upper right pins (from left to right on the upper row they are called F-E-D-C-B-A).
Turn on ignition but do not start, If everything works like it should, your fan(s) should come on now.
Either way, the SES light should start to blink now, short blinks followed by long blinks.
12 (one short followed by two long ones) allways comes first and is not a failure code, every code is shown three times in a row so you have time to write them down.
See what you come up with.
Also the lcd has code 12, then _ _ _ come up! (while this happens it looks like it is running through a sequence eg 1,2,..5...8,9 then 10)
And stays at 10 with _ _ _ until i take out the short!
No codes!
guess i will just buy another cts! maybe it's not reading the write reading!
Pro
Joined: May 2006
Posts: 637
Likes: 0
If you have the electronic AC, RPO C68, it has the digital readout.
http://www.digitalcorvettes.com/foru...ight=C68+codes
http://www.digitalcorvettes.com/foru...ight=C68+codes
Pro
Joined: May 2006
Posts: 637
Likes: 0
Good question, but I would not know how to tr. shoot it then.
Maybe someone with a manual AC here on the forum knows.
I get the impression there are quite a number of later model C4´s that have those manual AC´s.........
What would even be the benefit of such one?
What was the price difference back then between a manual and a automatic when they were new?
Little off topic maybe, but anyway...
Maybe someone with a manual AC here on the forum knows.
I get the impression there are quite a number of later model C4´s that have those manual AC´s.........
What would even be the benefit of such one?
What was the price difference back then between a manual and a automatic when they were new?
Little off topic maybe, but anyway...