Caspers Fan Switch - Larger Relay?
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Melting Slicks
Joined: Nov 2006
Posts: 2,001
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From: Ventura, California
Caspers Fan Switch - Larger Relay?
I'm installing a Caspers fan override switch. I've read that the stock fan relay can possibly overheat and fail when the fan is run on full-blast. Is there a solution or work around for this?
Race Director
Joined: Dec 2013
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Initial problem is the fan connector on the side of the radiator burning up when the fan is over driven too much, and when that connector is by passed and wired straight through, then its the PWM that burns up next.
So short version, since the PWM is really controlling the pulse to ground for the fan to control speed, best by pass for the fan on full blast, is to intercept the ground off the fan before it returns to the PWM, and to jump that wire directly to ground isntead. Granted that if you do run the fan long enough on full blast, your back to burning up the raditor side connector.
As for if your going to just way over ride the Ecm fan stock ratios/ need to wire in a direct over ride, then ditch the stock PWM and it wiring completely, and use a SSR as the PWM instead.
https://www.corvetteforum.com/forums...ring-help.html
As for fan, it a brush unit, so the harder you run it, the faster you are going to wear out the brushes and bearing.. There is stepping up to a brush less unit to take that out of the equation, but still will be the same for the motor bearings.
Really, need to back off of this up, since the stock cooling system can only be pushed so far, and if you are running into over heating problems, then it's really time to upgrade the entire cooling system to one that will cool the motor off better isntead. Hence stock raditor fan was not designed to run much to begin with (stop lights and such) and the car moving really generates enough air through the radiator that the fan running is not needed isntead on a stock motor.
To add, the kit will have the fan running when the motor is shut off, and will drain the battery if you forget to put the switch back in the O center position once the car is shut down. Also, it's using the factory wiring as well for power to the fan, so plan that the upper radiator passenger side connector is going to do a melt down in time as well.
https://www.installationinstructions.com/102159.pdf
So short version, since the PWM is really controlling the pulse to ground for the fan to control speed, best by pass for the fan on full blast, is to intercept the ground off the fan before it returns to the PWM, and to jump that wire directly to ground isntead. Granted that if you do run the fan long enough on full blast, your back to burning up the raditor side connector.
As for if your going to just way over ride the Ecm fan stock ratios/ need to wire in a direct over ride, then ditch the stock PWM and it wiring completely, and use a SSR as the PWM instead.
https://www.corvetteforum.com/forums...ring-help.html
As for fan, it a brush unit, so the harder you run it, the faster you are going to wear out the brushes and bearing.. There is stepping up to a brush less unit to take that out of the equation, but still will be the same for the motor bearings.
Really, need to back off of this up, since the stock cooling system can only be pushed so far, and if you are running into over heating problems, then it's really time to upgrade the entire cooling system to one that will cool the motor off better isntead. Hence stock raditor fan was not designed to run much to begin with (stop lights and such) and the car moving really generates enough air through the radiator that the fan running is not needed isntead on a stock motor.
To add, the kit will have the fan running when the motor is shut off, and will drain the battery if you forget to put the switch back in the O center position once the car is shut down. Also, it's using the factory wiring as well for power to the fan, so plan that the upper radiator passenger side connector is going to do a melt down in time as well.
https://www.installationinstructions.com/102159.pdf
Last edited by Dano523; Jan 24, 2022 at 06:16 PM.
