AC and Co0ling Fans
Thread Starter
Melting Slicks
Joined: Apr 2008
Posts: 2,703
Likes: 167
From: Western Washington
AC and Co0ling Fans
Just want to make sure I have this right in my head. This is concerning the air conditioning. When I start the car cold and turn on the AC the fans don't turn on automatically. It is only when the car is up to 185 degrees the the fan will kick in when the AC is turned on, is this correct. It is a 1999. Thank you.
Last edited by narlee; Aug 26, 2021 at 02:43 PM.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,643
Likes: 4,082
From: Cape Coral, Florida
You don’t have it right in your head !!…when you turn the AC on when the engine is cold the cooling fans will come on…mine turn on automatically albeit at low speed !!
Last edited by C5 Diag; Aug 26, 2021 at 03:01 PM.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,643
Likes: 4,082
From: Cape Coral, Florida
Thread Starter
Melting Slicks
Joined: Apr 2008
Posts: 2,703
Likes: 167
From: Western Washington
When I start the car cold no cooling fans come on. Well, not sure if the driver side fan comes on, hard to see for sure, trying to get a mirror positioned to see for sure.
Last edited by narlee; Aug 26, 2021 at 03:30 PM.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,643
Likes: 4,082
From: Cape Coral, Florida
Yes, the drivers side is difficult to see without a mirror…just look at the right side…don’t know your mechanical skills or what tools you possess so I won’t tell you how to diagnose it at this time !!
Last edited by C5 Diag; Aug 30, 2021 at 02:14 PM.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,643
Likes: 4,082
From: Cape Coral, Florida
Do you have a wiring diagram ??…first thing I’d check are fuses and maybe start swapping relays…you can use the horn relay for 2 of the 3 relays…the 3rd relay is a 5 bladed relay !!…if you have a jumper wire, a 12 volt test light that would be enough tooling for now !!
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Thread Starter
Melting Slicks
Joined: Apr 2008
Posts: 2,703
Likes: 167
From: Western Washington
Ok, I'm back. What I have so far is the fuses are good, the relays are good, the fans both work. Cold start, AC on, after a few minutes the passenger side fan cycles on for a short time then goes back on and every few minutes cycles on and off.
Racer
Joined: Aug 2004
Posts: 438
Likes: 15
From: satellite beach fl
https://www.corvetteforum.com/forums...coming-on.html
Check my posts in the above thread. Mine would start in low but only right fan would go high.
At 160 it is condenser pressure triggering fans.
Check my posts in the above thread. Mine would start in low but only right fan would go high.
At 160 it is condenser pressure triggering fans.
Racer
Joined: Aug 2004
Posts: 438
Likes: 15
From: satellite beach fl
If your fans are not coming on in low it would appear to be relay 45 related. Sequence is A/C on relay 45 energizes at 185 deg or 219psi and stays energized {in this case because you don't have low speed fans} till 255 psi is reached and relays 43 and 44 energize bringing in high speed fans {in your case only right hand}. Relays 43 and 44 would cycle between 255psi on and 219psi off. I would remove relay 45 or fuse 49 and test run engine, I would expect the same results you are having now. Check that relay 45 is inserted in the proper direction.
Thread Starter
Melting Slicks
Joined: Apr 2008
Posts: 2,703
Likes: 167
From: Western Washington
Also want to add the I said earlier it came on high speed but got to thinking it was low speed so I went and double checked. Cold car ac on no fans on startup but a few minutes later the passenger side fan only cycles on and off on LOW speed. Sorry for the misstatement earlier.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,643
Likes: 4,082
From: Cape Coral, Florida
If your fans are not coming on in low it would appear to be relay 45 related. Sequence is A/C on relay 45 energizes at 185 deg or 219psi and stays energized {in this case because you don't have low speed fans} till 255 psi is reached and relays 43 and 44 energize bringing in high speed fans {in your case only right hand}. Relays 43 and 44 would cycle between 255psi on and 219psi off. I would remove relay 45 or fuse 49 and test run engine, I would expect the same results you are having now. Check that relay 45 is inserted in the proper direction.