Electric fan bypass switch

[pontiacgp]

to have the fans shut down when you shut down the car you have to have the power to the fans on a switched cucuit meaning the power will come on only when the car is running or the key is in run position.

 

[Wageslave]

gotcha, mine are controlled by sending unit and relays. Looking for a timer

You can use a time delay relay from a 94-98 Dodge Ram to give you 90 or so seconds of run time after the ignition is turned off.

Those relays are used for the halo light around the ignition switch and can be found in the fusebox.

 

[84cutspreme]

Okay what led me to this was in instructions for fan wiring they mention to hook 12vpower to relay to be always on. This made no sense because (temp sender which grounds to complete circuit and power fans is in intake manifold rear water passage on driver side) would run for a long time to satisfy temp to below 175. however I knew on turbo cars such as Gran Natls they had a timer to run fans after shutdown...I thought I was led to believe they only really ran in an effort to cool turbo down because they were notorious for baking oil in turbo if left hot which led to startup of dry turbo and eventual failure. So all and all if it was real easy to add timer to my current fan relay setup to run after shutdown for about 2-3mins it seemed like a good idea...however it seems pretty difficult and/or expensive so I will be wiring them to power on in acc and run only. Thank you all for input and support👍🏻

 

[Wageslave]

You might want to consider wiring it for run only. I had mine set up like that for a while, and it was annoying having the fans come on any time i turned the key to accessory to listen to the radio.

 

[84cutspreme]

You might want to consider wiring it for run only. I had mine set up like that for a while, and it was annoying having the fans come on any time i turned the key to accessory to listen to the radio.

Its funny you would say that bc my father just siad the same thing

 

[84cutspreme]

side question. Is it possible to wire a ground switch to illuminate? What I mean is can I get light to light when switch is in the on position while only switching ground? regular illuminated switch like in picture

 

[fleming442]

No.

 

[UNGN]

side question. Is it possible to wire a ground switch to illuminate? What I mean is can I get light to light when switch is in the on position while only switching ground? regular illuminated switch like in picture

View attachment 92974

With a switch + a relay you can. Switch controls relay, relay switches ground wire on/off.

 

[84cutspreme]

With a switch + a relay you can. Switch controls relay, relay switches ground wire on/off.

I originally wanted to do that but SPAL recommends only using ground switch and not interrupting 12volt

 

[UNGN]

I originally wanted to do that but SPAL recommends only using ground switch and not interrupting 12volt

Spal recommends using a relay to turn on their fans. I don't think they care if you use a relay to turn on/off the relay that turns on their fans.

The ground wire being switched is the thermal switch ground, not the fan ground.