Electric fan wiring
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 4,871
Likes: 15
From: Detroit's West Side MI
Electric fan wiring
What's the best way to stand alone wire the electric fans?
The Painless kit looks like what I need, it includes a thermostat (200* on 185* off), relay, and the proper wiring.
Do I need two kits to keep the fans at different temps, or can I just wire them together so they both turn on at the same temp?
Also, will one relay be high enough current capability to handle two, or should I add a second 30A fuse and relay?
The Painless kit looks like what I need, it includes a thermostat (200* on 185* off), relay, and the proper wiring.
Do I need two kits to keep the fans at different temps, or can I just wire them together so they both turn on at the same temp?
Also, will one relay be high enough current capability to handle two, or should I add a second 30A fuse and relay?
Melting Slicks
Joined: Oct 2002
Posts: 3,193
Likes: 1
From: Cincinnati Oh
Just hook both fans (pusher and puller) up to one 30Amp relay. The relay will likely have a second "power" line if made specifically for automotive fan use (like the kinds you get in the parts stores), but if not then no biggie. Wire both fans in parallel off the 30 amp relayed circuit and then they'll both come on /turn off at the temps you mentioned. Just be sure to use good solid wiring (multistranded with thick insulation) and go a size over what you think you need for the current. For 30 amps, a 14 guage would be overkill but that's what I tend to use. You can keep the relay close to the radiator (for the thermometer function) and just run one single wire to the battery, then ground on the chassis by the radiator. Keeps the wiring clean. You wouldn't NEED to use the painless relay kit with thermostat, but it makes it easier than using a cylinderhead temperature sensor.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
I know on my 87 I wired it so both fans come on together at 200, and off at 185-incidentally the main fan on at least the 87 was operated by the ECM, but it's easy to bypass this-but I thought on a 93 you had to have the computer reprogammed-new chip or whatever?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by ScaryFast
Do I need two kits to keep the fans at different temps, or can I just wire them together so they both turn on at the same temp?
Yes, you will need two kits (or other means of activation) if you want them to come on at different temps. Yes, you can just wire them together if you want then to both turn on at the same time (bad idea).
Originally Posted by ScaryFast
Also, will one relay be high enough current capability to handle two, or should I add a second 30A fuse and relay?
RACE ON!!!
Thread Starter
Safety Car
Joined: Jul 2001
Posts: 4,871
Likes: 15
From: Detroit's West Side MI
Originally Posted by CFI-EFI
YES!
Yes, you will need two kits (or other means of activation) if you want them to come on at different temps. Yes, you can just wire them together if you want then to both turn on at the same time (bad idea).
RACE ON!!!
Yes, you will need two kits (or other means of activation) if you want them to come on at different temps. Yes, you can just wire them together if you want then to both turn on at the same time (bad idea).
RACE ON!!!
The car is a road race car only. I didn't provide much info in the original post but for clarification it becomes relevant.
I can easily stage the two kits and have a 185 and a 200 turn on temp, but is that more necessary for a street application, or is there a compelling reason to keep them separate in a track car?
Thanks for the info.
Burning Brakes
Joined: Jun 2004
Posts: 752
Likes: 0
From: richardson tx
i went with the painless setup but i didnt change my 160 stat. you get the relay, temp switch, fuse block and wiring. real simple deal for 50 bucks. thats for one fan i guess you could run two fans off one relay but they would come on at the same time. as far as the two fans coming on at diffrent times seems you would need two different rated temp switches????
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by ScaryFast
CFI - why do you suggest that it is a bad idea to turn them on at the same time? Too much cooling?
Originally Posted by ScaryFast
I can easily stage the two kits and have a 185 and a 200 turn on temp, but is that more necessary for a street application, or is there a compelling reason to keep them separate in a track car?
RACE ON!!!
Melting Slicks
Joined: Oct 2002
Posts: 3,193
Likes: 1
From: Cincinnati Oh
Not sure if I would lose as much sleep as CFI does on the difference between 185* and 205*. Having the fans come on at a lower temp will result in them running longer than stock, but when the OEM fan lasts 20 years... not sure I'd be TOO worried about fan wear. 
Secondly, amperage draw is a consideration, but again not sure it's REALLY that big of a deal.
IMHO, this boils down to preference. If you're retentive and want the car to run that extra 5-15 temps cooler then you accept the tradeoffs of maybe buying one extra fan before the car falls apart; and of course a little less gas mileage from all that added engine load at idle (surely it will add up). Conversely, if you're retentive and want to avoid those little caveats, then keep the bastich stock and run those 230 degree temps for better emissions.
Pick one, wire it well, enjoy.
Secondly, amperage draw is a consideration, but again not sure it's REALLY that big of a deal.IMHO, this boils down to preference. If you're retentive and want the car to run that extra 5-15 temps cooler then you accept the tradeoffs of maybe buying one extra fan before the car falls apart; and of course a little less gas mileage from all that added engine load at idle (surely it will add up). Conversely, if you're retentive and want to avoid those little caveats, then keep the bastich stock and run those 230 degree temps for better emissions.
Pick one, wire it well, enjoy.
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Burning Brakes
Joined: Jun 2004
Posts: 752
Likes: 0
From: richardson tx
Originally Posted by MR NICE
I want to hook up a simple switch to turn fan on when at the bank,fast food drive thru or traffic jam,once i'm rolling she runs about 190*
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
My fans hardly ever come on-never when cruising or in winter months.
They both come at the same time only when I get in traffic jams-or sitting for a long time ideling in hot weather.I can almost see the 180 thermostat opening, my temps get up to 185 in city driving, then cool to about 175-178-the temps stay in that range-unless the afore mentioned. My aux. fan is original-87, I did replace my main fan, but that was prior to changing the system, that was about 3 years ago, I did blow a fusible link, not long ago to the main fan relay-but the aux. still came on. I'm happy with my setup.BTW, mine are setup to come on at 200, and shut off at 185.
They both come at the same time only when I get in traffic jams-or sitting for a long time ideling in hot weather.I can almost see the 180 thermostat opening, my temps get up to 185 in city driving, then cool to about 175-178-the temps stay in that range-unless the afore mentioned. My aux. fan is original-87, I did replace my main fan, but that was prior to changing the system, that was about 3 years ago, I did blow a fusible link, not long ago to the main fan relay-but the aux. still came on. I'm happy with my setup.BTW, mine are setup to come on at 200, and shut off at 185.
