key off, automatic fans???

[mitsubluetalon]

hey guys, i have a cooling question. not a problem just i would like to make a modification to the system. i noticed that both fans run when the a/c button is pushed even with the car off but key ON. i was wondering if there is a way i can make my fans come on automatically when my key is out of the ignition.

(e.g.) when i turn my car off, i would like my fans to stay running for a couple of minutes, or if it is just plain hot outside. just to activate automatically through temperature with the key out.

i do have a turbo timer built into my starter/alarm system. and i use it all the time, but i would just like to have my fans come on whenever it gets to a certain temp.

has anybody ever done this mod before. or anybody have any theories as to how i can acomplish this? any help would be awesome.

thank you.

Jason.

 

[eclipsegsx1736]

EDIT: I just realized you have a 1g, i dont know if this mod will work.


I just finished wiring my stock fans following a VFAQ instruction. Its very easy, and here's what it does after the mod:

1. Whenever the ECU decides your cooling fan should come on, the A/C fan comes on as well, to help cool the radiator better. (Basically the mod makes it so whenever one fan is on, the other comes on too)
2. It allows you, using a simple toggle switch inside the cockpit, to override the ECU's control over the fans, so you can turn both fans on with the flip of a switch. So, you can leave the fans on even when the car is off, say to cool the engine faster if you need it to be cold to work on it, or to prevent overheating after shutting the engine off.
3. If you don't override the ECU's signal and leave the switch OFF, the fans will still come on when the ECU decides they should come on. So you dont have to worry about remembering to turn on your fans in case you forget.
4. The only disadvantage is that you could theoretically forget and leave the fans running with the switch ON after the engine is off, and run your battery down. But the fans are kinda noisy, you wont forget.


I did this mod, and its awesome. It was simple and its great to have control over the fans, and now I can actually use the A/C fan for something, because I NEVER use the A/C while driving, so normally the fan never gets used. I see no disadvantage, just be sure to wire it neatly, so the wire that has to travel thru your engine bay doesnt get tangled in the throttle linkage or something. I dont really know if its possible to wire it to a timer or something, but you can probably find a time-activated switch you could use. Just make sure it can handle the amps.

http://www.vfaq.com/mods/wayback/2gcoolingfan.html

 

[ndilo21]

You could hook them up to a turbo timer to get them to stay on.

 

[danielbui]

you can install an external thermostat w/ a probe that activates the fans at a certain temp. wire it directly to your battery with heavy gauge wire. make sure you have a new or good condition battery so while your car is in the off position it won't drain your battery. even though it should cool before killing your battery. an old battery during this operation can certainly leave you stranded. i don't see anything wrong with it. VW, Honda's, and other car manufactures already have this feature installed factory. check with all the autoparts stores around your area then start online. JEGS, Summit racing are some you might try as well. just tell them what your trying to do. good luck

 

[mitsubluetalon]

hey thanks guys, thats some good info. i thought about just incorporating the fans into the turbo timer system and thats definatly a good idea. my fathers 89 audi quatro had the intercooler fan come on whenever it gets hot, even when its not running. i thought that was a COOL idea. no pun intended................i was thinking about putting a fan behind my intercooler for the same purpose, but i was worried how it would affect airflow while the car is in "operation" hence my question. i wouldn't mind doing it for my rad fans as well, have the turbo and rad cool and have the car totally off......... i will be checking out some hardware stores and seeing what i can think up........so thanks everybody and i'll let you guys no how it goes.

jason.

 

[Sharkcus]

I am curious to see how it goes, but one thing though...

If you turn the fans on after the car is off, your waterpump isn't working anymore, so you are effectively just cooling the water that is already in the radiator, it won't be circulated anywhere. Maybe a little bit from expansion/contraction, but nothing significant. What are you hoping to accomplish?

 

[mitsubluetalon]

well that is something i've thought of, why have the fans run if its not actually cooling the engine. this post was more to do with the intercooler fan idea. just to see what kind of parts and cost involved, but to have my rad fans run automatically without the key would help more to help with keeping the turbo and area cooler after shut off, or perhaps after turbo timer shut off.

the turbo timer allows the water pump to run and to flow at a normal state. cooling the engine and internal components. but having the car idle for 2 mintues under 85-90 degree weather, still has the engine bay really hot after timer shut off. my thinking was that just having the fans run after turbo timer, or normal shut off would help to cool the engine bay down to a lower state thereby reducing thermal breakdown of external engine components such as rubber components, warpage control, exhaust manifold cracks, turbo compressor and exhaust housings, burnt fingers, etc.

my dads old 89 audi did this by itself and its an imaculate car today. i feel it is also kind of a neat idea for a car to monitor and control itself............and really like everything else i've ever done, its even just to see if i can do it.........maybe i'll find some other use for this....but again, thanks for the replies guys......

Jason.

 

[Burnett03]

when i shut my car off if the temp is still high my fans continue to run. Basically in the fuse box under the hood is a wire that runs the fan relay.. It is an ignition wire that turns the fans on when needed ONLY when the ignition is one. I cut this wire and sent it to the battery to give it 12volts all the time. So when i shut the car off the fans will keep running if its hot (like hondas' do)

 

[mitsubluetalon]

hey thats awesome! would you happen to have a picture of which wire or a better description of where it is?

 

[Defiant]

if it is just plain hot outside. just to activate automatically through temperature with the key out.

You're never going to see high enough ambient temps (oooh, all the way to 88° in Alberta?) for this part to make sense. Start up any car in the hottest weather any DSM will be exposed to (less than 120°F, most likely), and the temp gauge will still be showing "cold".
You can wire up the fans to run-on when hot with a simple GM fan switch. I've had one on my 2000 for fifteen years. You'll be surprised how short a time it'll run with the engine off, they cool down within about three minutes.

 

[Attack Eagle]

The other think to remember is it will be a big PITA if you CANT turn the fans off to get under teh hood, make sure you add a PIN switch to the hood to deactivate your new circuit and turn them off if the hood is opened w/ key off.

 

[mitsubluetalon]

all very good replies and information. thankyou.........