fan switch

[chevyhed53]

I'm sure this has been covered extensively, but ...
I have an electric fan wired through a 30/40-amp relay, that runs off ACC power (when the key is on the fan is on). I want to put a simple rocker switch in line so that I can control the fan manually. The books I have show the switch being wired into the 86 terminal on the relay. Is this correct? Any other advice is appreciated. Thanks!

[1project2many]

Terminals 85 and 88 are connected to the relay coil Power and ground applied to these terminals energizes the coil and turns the relay "on." I would install the rocker switch in between the ACC terminal and the relay on the power line. I would also make sure to use a 5A fuse in the power line to prevent accidental shorts from causing big problems.

[_Ogre]

85 and 86, but you get his drift
why it's not 1 thru 5 i have no idea


also: say goodbye to your motor

the first time you forget to turn on the fan you will overheat and ruin the motor
sorry, don't be stupid.
install a temp sensor or goodbye motor

[mongocanfly]

I'm going with ogre on this one..don't rely on remembering to flip on a fan switch..I had my drag car setup this way and I can't tell you how many times I "forgot" to flip that dang switch..finally put a big light on it..but that's just me..

[Donaldo]

I suggest powering it directly from a 12 volt source, as is it does no good with the key off.....

[1project2many]

Yeah, 86. Typo followed up with poor eyesight.

A temp switch from an '82 Cavalier. works well. With two switches the fan can be turned on manually but if you forget the temp switch does the job for you.

[chevyhed53]

Thanks all! I'll probably do both switch and sensor.

[dwcsr]

Typically you would run the acc to the relay coil and put the thermo switch on the ground site of the relay coil. from there you can splice a wire from that thermos switch to a toggle in the car and to ground so it would operate normally via the thermo switch and you have a manual over ride if you need it.

[chevyhed53]

OK, here's the weird thing: The way my fan is currently wired through the relay (and it works fine) is that positive from the battery is wired directly to the 87 terminal on the relay. Shouldn't it go to 30? Right now, 30 and 85 go to the fan, and 86 goes to ground. As I say, it works fine, but it is the opposite of every piece of info I have!

[dwcsr]

Originally Posted by chevyhed53

OK, here's the weird thing: The way my fan is currently wired through the relay (and it works fine) is that positive from the battery is wired directly to the 87 terminal on the relay. Shouldn't it go to 30? Right now, 30 and 85 go to the fan, and 86 goes to ground. As I say, it works fine, but it is the opposite of every piece of info I have!

power into 30 and out of 87. 86 relay coil 12v, 85 ground or thermos switch

[1project2many]

30 and 87 are opposite sides of the relay "closed" contacts. Power can go to either terminal and the relay will work. But the "correct" way is to run power to 30.

[chevyhed53]

Thanks for the help. I will wire it correctly when I get my switch!