Another coolant fan question
Thread Starter
Instructor
Joined: Dec 2005
Posts: 142
Likes: 2
From: Centerport NY
Another coolant fan question
I read through some of the threads on the cooling issues and the electric fans. From what I gather the ECM controls the fan operation - ( I have a 1990 )
My coolant fans are not turning on except with the AC is turned on. The temp comes up past 240 and the fans still do not turn on.
I have recently been checking codes with the A-B ports jumped out and the fans come on(?)
Could I have shorted something out?
Could it be a sensor? I previously changed the coolant temp. sensor
Or could it be 1 of the fan relays?
Any ideas??
Thanks
flatbush862
My coolant fans are not turning on except with the AC is turned on. The temp comes up past 240 and the fans still do not turn on.
I have recently been checking codes with the A-B ports jumped out and the fans come on(?)
Could I have shorted something out?
Could it be a sensor? I previously changed the coolant temp. sensor
Or could it be 1 of the fan relays?
Any ideas??
Thanks
flatbush862
Pro
Joined: May 2006
Posts: 536
Likes: 0
From: Humble Texas
I read through some of the threads on the cooling issues and the electric fans. From what I gather the ECM controls the fan operation - ( I have a 1990 )
My coolant fans are not turning on except with the AC is turned on. The temp comes up past 240 and the fans still do not turn on.
I have recently been checking codes with the A-B ports jumped out and the fans come on(?)
Could I have shorted something out?
Could it be a sensor? I previously changed the coolant temp. sensor
Or could it be 1 of the fan relays?
Any ideas??
Thanks
flatbush862
My coolant fans are not turning on except with the AC is turned on. The temp comes up past 240 and the fans still do not turn on.
I have recently been checking codes with the A-B ports jumped out and the fans come on(?)
Could I have shorted something out?
Could it be a sensor? I previously changed the coolant temp. sensor
Or could it be 1 of the fan relays?
Any ideas??
Thanks
flatbush862
interesting, my 96 does the same thing , i have to run a/c year round
and use temp comtrol...
be nice if someone had an answer..
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
I read through some of the threads on the cooling issues and the electric fans. From what I gather the ECM controls the fan operation - ( I have a 1990 )
My coolant fans are not turning on except with the AC is turned on. The temp comes up past 240 and the fans still do not turn on.
I have recently been checking codes with the A-B ports jumped out and the fans come on(?)
Could I have shorted something out?
Could it be a sensor? I previously changed the coolant temp. sensor
Or could it be 1 of the fan relays?
Any ideas??
Thanks
flatbush862
My coolant fans are not turning on except with the AC is turned on. The temp comes up past 240 and the fans still do not turn on.
I have recently been checking codes with the A-B ports jumped out and the fans come on(?)
Could I have shorted something out?
Could it be a sensor? I previously changed the coolant temp. sensor
Or could it be 1 of the fan relays?
Any ideas??
Thanks
flatbush862
Since during 'diagnostic' mode the fans came on, and went off after you pulled the 'jumper' (my assumption), doubtful you shorted anything.
Which coolant temp sensor did you replace (location/prongs)?
What dash gauge are you looking at when you noted '240' degree temps (digital or analog).
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
And it is not the wiring from the ECM to the relays either since they work in diagnostic' mode.
As stated need to determine the actual engine temp when fans engage
Thread Starter
Instructor
Joined: Dec 2005
Posts: 142
Likes: 2
From: Centerport NY
It's not the fan relays as otherwise the fans would not come on at all.
Since during 'diagnostic' mode the fans came on, and went off after you pulled the 'jumper' (my assumption), doubtful you shorted anything.
Which coolant temp sensor did you replace (location/prongs)?
What dash gauge are you looking at when you noted '240' degree temps (digital or analog).
Since during 'diagnostic' mode the fans came on, and went off after you pulled the 'jumper' (my assumption), doubtful you shorted anything.
Which coolant temp sensor did you replace (location/prongs)?
What dash gauge are you looking at when you noted '240' degree temps (digital or analog).
I replaced the coolant sensor at the front of the intake manifold below the thermostat. I also replaced the temp. gauge sensor on the right head.
I have an analog gauge and I guestimated 240 as it approached the
"260" mark.
What tells the ECM to turn on the fans and could the ECM be a problem??..... I recently re-installed the stock PROM. I will be re-installing my PCM for less chip. But the problem started before the re-installation of the stock chip.
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Safety Car
Joined: Oct 2008
Posts: 4,689
Likes: 4
From: Yucaipa CA
Just take the threaded in plug out of the left head and put a thermal sensor for a f-body in, run a wire from it to both the relays ground wire. I think one is blue with white stripe and the other is blue with black stripe. that will end you cooling issues and take away control from the ecm. I gave up on getting the ecm on my 90 to run the fans now they work perfectly.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
You are chasing Mods....there must be a reason your temps are reaching 240° to begin with......
I'd start with that first.
Making Mods or wondering why auxiliary cooling systems aren't coming on sooner is OK...but why are they needed?? That is the question that no one attempts to pose
I'd start with that first.
Making Mods or wondering why auxiliary cooling systems aren't coming on sooner is OK...but why are they needed?? That is the question that no one attempts to pose
Thread Starter
Instructor
Joined: Dec 2005
Posts: 142
Likes: 2
From: Centerport NY
OK- so the "chip" meaning my PCM for less chip, signals the relays to turn on the fans. But what sensor tells the chip to tell the relay to tell the fan .. thats what I am trying to get at
I know of a Coolant Temp. Sensor in the intake man., a Temp gauge sensor in the right head .... is there another sensor "Fan sensor" - such as below - that independently indicates to the chip to turn the fan on?
http://hypertech.com/Products/Cool%20Fan%20Switch
where does this plug in?? and does it work??
Flatbush862
I know of a Coolant Temp. Sensor in the intake man., a Temp gauge sensor in the right head .... is there another sensor "Fan sensor" - such as below - that independently indicates to the chip to turn the fan on?
http://hypertech.com/Products/Cool%20Fan%20Switch
where does this plug in?? and does it work??
Flatbush862
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
OK...more direct approach
Flatbush, have you pulled your 20 year old radiator and had it boiled out??
If there is sediment (and the common theme is that there is a ton of sediment in the bottom of the radiator) in the bottom of your radiator....what % of your radiators capacity is diminished by that section being essentially blocked off??
If your radiator's capacity is diminished by ~7% would that not account for some of your rising temps??? I just pulled a percentage number out as I have no way of knowing either way....I'm just asking the question most ignore.
Have you pulled the shroud off and seen what is in between the condenser and radiator?? Since the two coolant hoses and the two tranny cooler hoses are hooked up, not to mention way too many screws, many put this off yet it is most common in C4s
So yeah, mods would are great fun and you can list them in your signature...
Flatbush, have you pulled your 20 year old radiator and had it boiled out??
If there is sediment (and the common theme is that there is a ton of sediment in the bottom of the radiator) in the bottom of your radiator....what % of your radiators capacity is diminished by that section being essentially blocked off??
If your radiator's capacity is diminished by ~7% would that not account for some of your rising temps??? I just pulled a percentage number out as I have no way of knowing either way....I'm just asking the question most ignore.
Have you pulled the shroud off and seen what is in between the condenser and radiator?? Since the two coolant hoses and the two tranny cooler hoses are hooked up, not to mention way too many screws, many put this off yet it is most common in C4s
So yeah, mods would are great fun and you can list them in your signature...
Safety Car
Joined: Oct 2008
Posts: 4,689
Likes: 4
From: Yucaipa CA
OK- so the "chip" meaning my PCM for less chip, signals the relays to turn on the fans. But what sensor tells the chip to tell the relay to tell the fan .. thats what I am trying to get at
I know of a Coolant Temp. Sensor in the intake man., a Temp gauge sensor in the right head .... is there another sensor "Fan sensor" - such as below - that independently indicates to the chip to turn the fan on?
http://hypertech.com/Products/Cool%20Fan%20Switch
where does this plug in?? and does it work??
Flatbush862
I know of a Coolant Temp. Sensor in the intake man., a Temp gauge sensor in the right head .... is there another sensor "Fan sensor" - such as below - that independently indicates to the chip to turn the fan on?
http://hypertech.com/Products/Cool%20Fan%20Switch
where does this plug in?? and does it work??
Flatbush862
Thread Starter
Instructor
Joined: Dec 2005
Posts: 142
Likes: 2
From: Centerport NY
OK...more direct approach
Flatbush, have you pulled your 20 year old radiator and had it boiled out??
If there is sediment (and the common theme is that there is a ton of sediment in the bottom of the radiator) in the bottom of your radiator....what % of your radiators capacity is diminished by that section being essentially blocked off??
If your radiator's capacity is diminished by ~7% would that not account for some of your rising temps??? I just pulled a percentage number out as I have no way of knowing either way....I'm just asking the question most ignore.
Have you pulled the shroud off and seen what is in between the condenser and radiator?? Since the two coolant hoses and the two tranny cooler hoses are hooked up, not to mention way too many screws, many put this off yet it is most common in C4s
So yeah, mods would are great fun and you can list them in your signature...
Flatbush, have you pulled your 20 year old radiator and had it boiled out??
If there is sediment (and the common theme is that there is a ton of sediment in the bottom of the radiator) in the bottom of your radiator....what % of your radiators capacity is diminished by that section being essentially blocked off??
If your radiator's capacity is diminished by ~7% would that not account for some of your rising temps??? I just pulled a percentage number out as I have no way of knowing either way....I'm just asking the question most ignore.
Have you pulled the shroud off and seen what is in between the condenser and radiator?? Since the two coolant hoses and the two tranny cooler hoses are hooked up, not to mention way too many screws, many put this off yet it is most common in C4s
So yeah, mods would are great fun and you can list them in your signature...
Jhammnd-
Yes I agree that the root cause of the overheating could be in the radiator. But it still does not address why the fans are not coming on.
I will flush out the radiator and take it from there.
Safety Car
Joined: Oct 2008
Posts: 4,689
Likes: 4
From: Yucaipa CA
if CTS is doing it's job, fans worked before so prom/clapack probably not the problem. Then the only thing left is a faulty ecm.
Racer
Joined: Jan 2007
Posts: 274
Likes: 0
From: Muskogee OK
Flatbush, if you have the C68 (electronic AC) you can verify what the sensor is reading by pushing both fan buttons until -00 shows on the AC display. Use the right button to scroll to -16 and push "AUTO". This will display the coolant temp in celsius, so you'll need a conversion table.
According to the FSM, the primary fan should activate at 226F (108 C) and the secondary at 239F (115C).
According to the FSM, the primary fan should activate at 226F (108 C) and the secondary at 239F (115C).