Go Back   Corvette Forum > C5 Corvettes, 1997 - 2004 > C5 Tech
Sign in using an external account
Register Forgot Password?
Register Search Today's Posts Mark Forums Read FAQ Vendor Directory
Search
C5 Tech
Corvette Tech/Performance: LS1 Corvette Technical Info, Internal Engine, External Engine, Tech Topics, Basic Tech, Maintenance, How to Remove & Replace Sponsored by
Karl Chevrolet

Welcome to Corvetteforum.com!
Welcome to Corvetteforum.com.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join Corvetteforum.com today!


Corvette Store
 
 
C7 Parts & Accessories
C6 Parts & Accessories
C5 Parts & Accessories
C4 Parts & Accessories
C3 Parts & Accessories
C2 Parts & Accessories
C1 Parts & Accessories
Wheels & Tires
Sponsored Ads
 
 
Vendor Directory
  
Reply
 
 
 
 
Thread Tools Search this Thread
Old 07-05-2011, 10:20 PM   #1
creep403
Junior Member
 
Member Since: Jul 2011
Location: Lindsay oklahoma
creep403
Default Cooling fans only work with a/c

Im a new member and a new to the world of Vette's.
I just bought a 98' A4 with 97k for $13.5k
I noticed when ac is off the fans will not come on, temp got to bout 230'ish. I turned ac on and sure enough fans came on and car cooled off. my digital and anolog gauges work fine ... is there another sensor responsible for the cooling fans? Thx ahead for any help
creep403 is offline   Reply With Quote
Old 07-05-2011, 11:27 PM   #2
Silverbullet00
CF Senior Member
 
Silverbullet00's Avatar
 
Member Since: Jan 2007
Location: Norman Oklahoma - The Only State in the Union with no Blue Counties!
Default

Quote:
Originally Posted by creep403 View Post
Im a new member and a new to the world of Vette's.
I just bought a 98' A4 with 97k for $13.5k
I noticed when ac is off the fans will not come on, temp got to bout 230'ish. I turned ac on and sure enough fans came on and car cooled off. my digital and anolog gauges work fine ... is there another sensor responsible for the cooling fans? Thx ahead for any help

Standing still or moving? 230 is way to high with or without a/c! Your engine is fine even with higher temps but it is not good. A tuner can turn your fans on at lower engine temps with a few key strokes. A 160 thermostat and a tune will help! Might be a good time to flush and refill the radiator,,,,like me,,, your car will show some age. Fall will also help.

My fans come on at 190ish now, Never have seen 230 even after cam swap and outside temp above 110!


My $00.02
Silverbullet00 is offline   Reply With Quote
Old 07-05-2011, 11:38 PM   #3
creep403
Junior Member
 
Member Since: Jul 2011
Location: Lindsay oklahoma
creep403
Default

fans work fine as long as the ac is on. is there a seperate sensor other than temp gauge sensor that controls fans?

nice car btw
creep403 is offline   Reply With Quote
Old 07-05-2011, 11:42 PM   #4
creep403
Junior Member
 
Member Since: Jul 2011
Location: Lindsay oklahoma
creep403
Default

also who in okc area tune's vette's
creep403 is offline   Reply With Quote
Old 07-06-2011, 06:56 PM   #5
lionelhutz
CF Senior Member
 
lionelhutz's Avatar
 
Member Since: Apr 2007
Location: South Western Ontario
Default

That's an odd one. The fans are controlled by the same relays and PCM wiring AC or temperature only.

Are they spinning fairly "softly" with the AC on? They should be on low with both in series which makes them fairly silent. Confirm they are both turning too.

I believe the stock hi fan temperature is 236 degrees so you'd have to let the temps get that high to see what happens when the hi fans are called for.

Peter
lionelhutz is offline   Reply With Quote
Old 07-06-2011, 11:35 PM   #6
creep403
Junior Member
 
Member Since: Jul 2011
Location: Lindsay oklahoma
creep403
Default

Quote:
Originally Posted by lionelhutz View Post
That's an odd one. The fans are controlled by the same relays and PCM wiring AC or temperature only.

Are they spinning fairly "softly" with the AC on? They should be on low with both in series which makes them fairly silent. Confirm they are both turning too.

I believe the stock hi fan temperature is 236 degrees so you'd have to let the temps get that high to see what happens when the hi fans are called for.

Peter
I'll give it a try, I havent heard the fans on low, with ac they go strait to high ... maybe a relay and if so which one?
creep403 is offline   Reply With Quote
Old 07-07-2011, 09:00 AM   #7
moosifer
CF Senior Member
 
Member Since: Oct 2009
Location: Roseville CA
Default

When the AC comes on the fans begin to run in high speed mode. If you are having trouble with low speed check the fuses first. My c5 through a dtc about low speed cooling fans not working and sure enough a fuse was blown. Search the forum for this problem and you should find information about what fuses to check and a handy wiring diagram that will show you how the fans operate. If the fuses are not blown I would check grounds or the relays.
moosifer is offline   Reply With Quote
Old 07-07-2011, 08:25 PM   #8
lionelhutz
CF Senior Member
 
lionelhutz's Avatar
 
Member Since: Apr 2007
Location: South Western Ontario
Default

Odd again, the fans should not run in high with the AC on. Take a good look around the under hood electrical center (the fuse block by the battery) and the wiring harnesses there and leading up towards the fans to see if something has been modified.


Quote:
Originally Posted by moosifer View Post
When the AC comes on the fans begin to run in high speed mode.
I don't believe this is correct. Mine run in low and I've read the posts here giving the service info which says the fans run in low with the AC on and the temps above 185 degrees. Here's the paragraph I copied which was posted as coming from the service manual:

The low speed cooling fan is commanded on when the coolant temperature reaches 108C (226F). It is turned off if the coolant temperature lowers to 104C (219F). The high speed cooling fan is commanded on when the coolant temperature reaches 113C (235F). It is turned off if the coolant temperature lowers to 108C (226F). When the A/C is on and the coolant temperature reaches 85C (185F), the low speed cooling fan will be turned on at vehicle speeds less than 56 kPh (35 mph).

Peter
lionelhutz is offline   Reply With Quote
Old 07-07-2011, 08:29 PM   #9
lionelhutz
CF Senior Member
 
lionelhutz's Avatar
 
Member Since: Apr 2007
Location: South Western Ontario
Default

Here's a thread with the fan wiring diagram;

http://forums.corvetteforum.com/c5-t...igh-speed.html

Peter
lionelhutz is offline   Reply With Quote
Old 07-08-2011, 12:10 AM   #10
Bill Dearborn
Tech Contributor
 
Bill Dearborn's Avatar
 
Member Since: Oct 1999
Location: Charlotte (formerly Endicott, NY) NC
Default

Here is a description of how the fans work and at what temps they are turned on and at what temps they go to high speed operation.
Cooling Fan Control
The engine cooling fan system consists of two electrical cooling fans and three fan relays. The relays are arranged in a series/parallel configuration that allows the powertrain control module (PCM) to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage and ignition 1 voltage from the underhood electrical center. The ground path is provided at G102.

During low speed operation, the PCM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan 1 relay coil, closes the relay contacts, and supplies battery positive voltage through the cooling fan motor supply voltage circuit to the left cooling fan. The ground path for the left cooling fan is through the cooling fan 3 relay and the right cooling fan. The result is a series circuit with both fans running at low speed.

During high speed operation the PCM supplies the ground path for the cooling fan 1 relay through the low speed cooling fan relay control circuit. After a 3-second delay, the PCM supplies a ground path for the cooling fan 2 relay and the cooling fan 3 relay through the high speed cooling fan relay control circuit. This energizes the cooling fan 3 relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the cooling fan 2 relay coil is energized closing the relay contacts and provides battery positive voltage on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have there own ground path. The result is a parallel circuit with both fans running at high speed.

The low speed cooling fan is commanded on when the coolant temperature reaches 108C (226F). It is turned off if the coolant temperature lowers to 104C (219F). The high speed cooling fan is commanded on when the coolant temperature reaches 113C (235F). It is turned off if the coolant temperature lowers to 108C (226F). When the A/C is on and the coolant temperature reaches 85C (185F), the low speed cooling fan will be turned on at vehicle speeds less than 56 kPh (35 mph).

People are always running around worrying about their temps because they see the numbers on the gauge. These cars are designed to work with high coolant temps and have no problems operating at the temps you indicate. As you can see the fans don't even get turned onto low speed until the temp hits 226 and don't go to high speed until the temp hits 235 degrees. At an autocross where we were running in heats and cycling through the runs quite fast I saw a 242 degree coolant temp on my C5Z for most of an event.

Bill
Bill Dearborn is offline   Reply With Quote
Old 07-08-2011, 07:28 PM   #11
Jumper11
CF Senior Member
 
Member Since: Mar 2011
Location: Mechanicsville Md
Default

My 02 cooling fans come on but I can hear them when I turn on the AC. They work as avertised without the AC on coming on at 226 and turning off at 219. I don't know if they're coming on low or high when without the AC.
Jumper11 is offline   Reply With Quote
Old 07-08-2011, 07:28 PM
 
Go Back   Corvette Forum > C5 Corvettes, 1997 - 2004 > C5 Tech
Reload this Page Cooling fans only work with a/c
 
 
 
Reply

Tags
2000, ac, c5, check, cooling, corvette, fan, fans, ground, high, on, radiator, turn, work, working, works


Thread Tools Search this Thread
Search this Thread:

Click for Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump


All times are GMT -4. The time now is 12:04 PM.


Emails & Password Backup

Search Engine Friendly URLs by vBSEO 3.5.2