Aux. Fan Question
Thread Starter
Instructor
Joined: Aug 2009
Posts: 150
Likes: 1
Aux. Fan Question
Hi ....Has anyone ever bypassed the aux fan temp sensor and set to fan to run all the time ?? I was thinking of connecting direct to alternator with a in-line 30a fuse . Dont like the idea that the fan comes on at 238 ..figured its easier to keep something cool rather than cool it down AFTER it heats up ...Any thoughts on this ?? pros/cons ??
Thanks ,Neal
Melting Slicks
Joined: Feb 2001
Posts: 2,608
Likes: 3
From: TEXAS - you mean there are other states?
I am learning in this area ..... but shouldn't it come on well before 238? maybe like 160/180? If I understand all, my DeWitts will come on at 160. That is controlled by teh temp sensor they supplied at the radiator.
Racer
Joined: Jan 2009
Posts: 482
Likes: 0
From: Near Round Top (pop. 90) Texas
Hi ....Has anyone ever bypassed the aux fan temp sensor and set to fan to run all the time ?? I was thinking of connecting direct to alternator with a in-line 30a fuse . Dont like the idea that the fan comes on at 238 ..figured its easier to keep something cool rather than cool it down AFTER it heats up ...Any thoughts on this ?? pros/cons ??
Thanks ,Neal
Thanks ,Neal
Advanced
Joined: Feb 2010
Posts: 83
Likes: 0
From: Dallas TX
If you really want to do something like that the safe & smart way would be to find the fan relay and find the wire that controls it. Probably a temp sensor that completes ground, so you can shunt it with a simple switch that connects the relay to ground to turn the fan on. Basically a manual switch wired in parallel with the sending unit, this allows you to keep stock function as well. Or you could try to find a lower temp sending unit (and ditch the water pump fan?)
Melting Slicks
Joined: May 2003
Posts: 2,078
Likes: 283
From: Dyersburg TN
fan switch
I put one from Jegs on to control mine. It has a probe mounted in the radiator and a **** to adjust when it comes on.
it cost 26.99
http://www.jegs.com/i/Flex-a-lite/400/31147/10002/-1
it cost 26.99
http://www.jegs.com/i/Flex-a-lite/400/31147/10002/-1
Thread Starter
Instructor
Joined: Aug 2009
Posts: 150
Likes: 1
According to my service manual , ther is no relay for the aux fan only a 30 amp circuit breaker... and the stock block mounted sensor will turn the fan on at 238* and shut it off when the temp gets down to 201*..ONLY when the ignition is in the run/on position... This is for an 81 so others may have a different set up...
seems like the GM designers thought 200+ was fine ...
seems like the GM designers thought 200+ was fine ...
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
According to my service manual , ther is no relay for the aux fan only a 30 amp circuit breaker... and the stock block mounted sensor will turn the fan on at 238* and shut it off when the temp gets down to 201*..ONLY when the ignition is in the run/on position... This is for an 81 so others may have a different set up...
seems like the GM designers thought 200+ was fine ...
seems like the GM designers thought 200+ was fine ...
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Same position as the drivers side head, don't think its any hotter. I always thought 238* was a bit late too. I think thats about the hottest spot on the heads, or pretty close to it, so it may not mean the motor or your coolant is actually at 238*. Will have to look into that once I am on the road again
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
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
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Burning Brakes
Joined: Jun 2009
Posts: 840
Likes: 4
From: Syracuse IN
Sixfooter, I also have an 81 with the auxilery fan. The temp probe in the head switches B- not B+ If you want to keep the fan on when ignition is on just complete the ground circuit. I installed a lower temp sensor/switch in the same location to come on at 185* Bought from Summit for $18.00. Works great. The aux fan does not come on after the engine is off though. No B+ relay either. Good luck Al
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
For some reason I thought the auxiliary electrical fan was part of the RPO ZN1 trailer package. Pulling a load will put the temps up pretty quickly.
Don't ask what was included with ZN1; I do not know. It appeared in 1979 and lasted through 1981. The unit numbers are:
1979 - 1,001
1980 - 796
1981 - 916
Don't ask what was included with ZN1; I do not know. It appeared in 1979 and lasted through 1981. The unit numbers are:
1979 - 1,001
1980 - 796
1981 - 916
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
My 1979 L-82 did not have that fan. But it did not have A/C; it was still an option that year although it became standard in 1980. So the fan might have been coupled with the A/C package.
Melting Slicks
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
my 79 L82 w/AC has the aux. fan, the supply voltage for the fan runs through the key switch !!!, i installed a jegs. fan relay kit with temp sensor in thermostat housing. i used the voltage from the key switch just to supply voltage to the relay coil, the fan now has full voltage from the starter / battery lug. it now comes on at 200 off at 185.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
my 79 L82 w/AC has the aux. fan, the supply voltage for the fan runs through the key switch !!!, i installed a jegs. fan relay kit with temp sensor in thermostat housing. i used the voltage from the key switch just to supply voltage to the relay coil, the fan now has full voltage from the starter / battery lug. it now comes on at 200 off at 185.
the relay coil can be hooked up to suit your control concepts....
but not to run main power off the battery terminal, it will take forever and a year to charge your battery IF that fan is running....
Pro
Joined: Oct 2005
Posts: 505
Likes: 8
From: Houston Tx.
I installed a 79 fan shroud and fan in my 76. Wired the fan with a relay to a switch under the dash. When it gets too warm, I flip it on. Works great. Stabilizes the temp immediately and starts bringing it down in minutes. Only works with the ignition on.
Melting Slicks
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
IMO, you should wire that main power to the relay/fan from the alt stud as a direct fused @40 amp wire....8 ga is good 10 will do.....
the relay coil can be hooked up to suit your control concepts....
but not to run main power off the battery terminal, it will take forever and a year to charge your battery IF that fan is running....
you are correct, this weekend we are installing dual fan spal setup, and supply power is coming straight from the alternator.
the relay coil can be hooked up to suit your control concepts....
but not to run main power off the battery terminal, it will take forever and a year to charge your battery IF that fan is running....
you are correct, this weekend we are installing dual fan spal setup, and supply power is coming straight from the alternator.
