Fan switch headache!
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Member
Joined: Dec 2011
Posts: 111
Likes: 1
From: pennslvania
Car: 1985 chevy camaro,z28
Engine: crate 350,headers,3in exhaust
Transmission: 700R4
Axle/Gears: 308------3.73 auburn unit
Fan switch headache!
Hey guys,
I have my car set up on a fan switch in the dash.
I know this is foolish but i havent changed the set up since i purchased the car.
I know i have a 35 amp switch but if i drive the car for more than 30 minutes the switch base gets blistering hot!
Just wondering how to run the fan factory and any thoughts on the issue thank you
I have my car set up on a fan switch in the dash.
I know this is foolish but i havent changed the set up since i purchased the car.
I know i have a 35 amp switch but if i drive the car for more than 30 minutes the switch base gets blistering hot!
Just wondering how to run the fan factory and any thoughts on the issue thank you
Supreme Member




Joined: Oct 2004
Posts: 4,528
Likes: 240
From: Henrietta NY
Car: 1984 Trans Am L69
Engine: Sniper EFI Powered 355
Transmission: WC T5 w/ Steel Support Plate
Axle/Gears: 3.42 10 Bolt Posi
Re: Fan switch headache!
You need to either switch a relay with your switch or wire a relay with a temp switch.
This may help I made it a bit ago.
This may help I made it a bit ago.
Junior Member
Joined: Jul 2014
Posts: 5
Likes: 0
Car: 92 camero rs 25th anniversary
Engine: V6 3.0
Transmission: Automatic
Re: Fan switch headache!
Where is this relay located cause I've noticed that my fan does not come on at all today I took out my coolant diverter valve and I started the car to see how the temp goes and noticed that the fan never turned on so maybe the relay is bad the temp did go down but the fan didn't come on to help
Supreme Member
Joined: Apr 2006
Posts: 4,482
Likes: 10
From: Northern, CA
Car: 1989 Iroc-Z Camaro
Engine: TBI,5.0
Transmission: Automatic 700R4
Axle/Gears: Eaton Posi,3.42,LPW Ultimate Cover
Re: Fan switch headache!
midias has the best diagram I have ever seen for returning a fan circuit to basically stock.
I'm not sure what temp. the sw555 switch is set at though.
Here's the Circuit I post as an alternative option =
A 180* thermostat ,with a fan switch that comes on at 190* is what I run.
Perfect IMO.
Here's the option =
Most will only need to install the switch on the ground wire. Others installing a aftermarket fan will need to run your fans positive wire to the main power junction terminal located near the battery ( with a inline fuse just before the connection. I use a 30amp ) and the fans ground like this.
Here's the "adjustable", temperature controlled switch for $17.99 and how you can wire it in. A very simple circuit.(do not use the diagram that comes with the switch)
You might need to put in the Part # 733653
http://www.autozone.com/autozone/par...er=267187_0_0_

I have two that are wired differently. A little more complex.
Side note = Its funny, I must have this diagram posted a hundred times. At least three times in just the last couple days. The reason I continue to post them is because I believe they can help solve the "I have a single fan but cant..........."problems easily.
IMO, to have "total" temp. control over a single basically stock size fan that will only cost you $17.99 and around 30 minutes to install is beyond simple.
I have other simple circuits for larger/higher amp fans as well.
I'm not sure what temp. the sw555 switch is set at though.
Here's the Circuit I post as an alternative option =
A 180* thermostat ,with a fan switch that comes on at 190* is what I run.
Perfect IMO.
Here's the option =
Most will only need to install the switch on the ground wire. Others installing a aftermarket fan will need to run your fans positive wire to the main power junction terminal located near the battery ( with a inline fuse just before the connection. I use a 30amp ) and the fans ground like this.
Here's the "adjustable", temperature controlled switch for $17.99 and how you can wire it in. A very simple circuit.(do not use the diagram that comes with the switch)
You might need to put in the Part # 733653
http://www.autozone.com/autozone/par...er=267187_0_0_

I have two that are wired differently. A little more complex.
Side note = Its funny, I must have this diagram posted a hundred times. At least three times in just the last couple days. The reason I continue to post them is because I believe they can help solve the "I have a single fan but cant..........."problems easily.
IMO, to have "total" temp. control over a single basically stock size fan that will only cost you $17.99 and around 30 minutes to install is beyond simple.
I have other simple circuits for larger/higher amp fans as well.
Last edited by Ron U.S.M.C.; Jul 20, 2014 at 12:36 AM.
Supreme Member




Joined: Oct 2004
Posts: 4,528
Likes: 240
From: Henrietta NY
Car: 1984 Trans Am L69
Engine: Sniper EFI Powered 355
Transmission: WC T5 w/ Steel Support Plate
Axle/Gears: 3.42 10 Bolt Posi
Re: Fan switch headache!
midias has the best diagram I have ever seen for returning a fan circuit to basically stock.
I'm not sure what temp. the sw555 switch is set at though.
Here's the Circuit I post as an alternative option =
A 180* thermostat ,with a fan switch that comes on at 190* is what I run.
Perfect IMO.
Here's the option =
Run your fans positive wire to the main power junction terminal located near the battery ( with a inline fuse just before the connection. I use a 30amp ) and the fans ground like this.
Here's the "adjustable", temperature controlled switch for $17.99 and how you can wire it in. A very simple circuit.
You might need to put in the Part # 733653
http://www.autozone.com/autozone/par...er=267187_0_0_

I have two that are wired differently. A little more complex.
Side note = Its funny, I must has this diagram posted a hundred times. At least three times in just the last couple days. The reason I continue to post them is because I believe they can help solve the "I have a single fan but cant..........."problems easily.
IMO, to have "total" temp. control over a single basically stock size fan that will only cost you $17.99 and around 30 minutes to install is beyond simple.
I have other simple circuits for larger/higher amp fans as well.
I'm not sure what temp. the sw555 switch is set at though.
Here's the Circuit I post as an alternative option =
A 180* thermostat ,with a fan switch that comes on at 190* is what I run.
Perfect IMO.
Here's the option =
Run your fans positive wire to the main power junction terminal located near the battery ( with a inline fuse just before the connection. I use a 30amp ) and the fans ground like this.
Here's the "adjustable", temperature controlled switch for $17.99 and how you can wire it in. A very simple circuit.
You might need to put in the Part # 733653
http://www.autozone.com/autozone/par...er=267187_0_0_

I have two that are wired differently. A little more complex.
Side note = Its funny, I must has this diagram posted a hundred times. At least three times in just the last couple days. The reason I continue to post them is because I believe they can help solve the "I have a single fan but cant..........."problems easily.
IMO, to have "total" temp. control over a single basically stock size fan that will only cost you $17.99 and around 30 minutes to install is beyond simple.
I have other simple circuits for larger/higher amp fans as well.
Supreme Member
Joined: Apr 2006
Posts: 4,482
Likes: 10
From: Northern, CA
Car: 1989 Iroc-Z Camaro
Engine: TBI,5.0
Transmission: Automatic 700R4
Axle/Gears: Eaton Posi,3.42,LPW Ultimate Cover
Re: Fan switch headache!
midias ,
I believe your diagram gets all the attention. Most must feel more confident using yours I'm sure.
This site has helped me MANY times, so it
feels nice when I can help someone in return.
I believe your diagram gets all the attention. Most must feel more confident using yours I'm sure.
This site has helped me MANY times, so it
feels nice when I can help someone in return.
Trending Topics
Joined: May 2009
Posts: 384
Likes: 16
From: Des Moines IA
Car: 89 forrmula
Engine: 350 TBI
Transmission: T-5
Axle/Gears: 3.55
Re: Fan switch headache!
The SW555 switch close contacts @ 238 I believe which works since the cylinder head nominally runs about 15-20 degrees hotter than the intake @ the t-stat. Its the same IMO as triggering the fan off a 218-on switch in the intake, which I prefer only to keep the wiring clean and tidy.
Supreme Member




Joined: Oct 2004
Posts: 4,528
Likes: 240
From: Henrietta NY
Car: 1984 Trans Am L69
Engine: Sniper EFI Powered 355
Transmission: WC T5 w/ Steel Support Plate
Axle/Gears: 3.42 10 Bolt Posi
Re: Fan switch headache!
The SW555 switch close contacts @ 238 I believe which works since the cylinder head nominally runs about 15-20 degrees hotter than the intake @ the t-stat. Its the same IMO as triggering the fan off a 218-on switch in the intake, which I prefer only to keep the wiring clean and tidy.
http://www.wellsve.com/custom_searches/ds_fans.php?switch=sw555&submit=Submit
Last edited by midias; Jul 20, 2014 at 12:06 PM.
Joined: May 2009
Posts: 384
Likes: 16
From: Des Moines IA
Car: 89 forrmula
Engine: 350 TBI
Transmission: T-5
Axle/Gears: 3.55
Re: Fan switch headache!
I looked that up just recently too-I wouldn't go that low for a cylinder head temp switch, possibly an SW500 would be a better switch for the cylinder head?
Supreme Member




Joined: Oct 2004
Posts: 4,528
Likes: 240
From: Henrietta NY
Car: 1984 Trans Am L69
Engine: Sniper EFI Powered 355
Transmission: WC T5 w/ Steel Support Plate
Axle/Gears: 3.42 10 Bolt Posi
Re: Fan switch headache!
Maybe but on my car the switch turns on when my mechanical gauge in the manifold is just under 210 and the IR temp gun on the head reads 212
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