For those of you looking to do this, there are a few diagrams floating around and having just done this mod over the weekend, i thought i'd save some people the frustration of which is the proper diagram.

If you buy/pull the thermo switch & thermo housing from a 4ac, chances are you got an "always closed" switch. When the car gets up to temp, the switch breaks the circuit and triggers the fan to turn on (this is the single wire 4ac switch most of you know about). The only way this will work properly is to run it with 2 SPDT relays, as shown in this link:

http://www.redlinedaily.com/automotive. ... an_install



i tried to use 2 other diagrams (i won't post them to avoid confusion) and the fans would either stay on with ignition or never turn on. Remember this is just a reference, please double check your wiring, information and always disconnect the battery when you're working on the electrical system in your car.

I'm assuming your using a ae82 or 92 t stat cover? Tell us more about your setup and how well it actually works for cooling / consistency. Any quirks?

Deuce Cam wrote:I'm assuming your using a ae82 or 92 t stat cover? Tell us more about your setup and how well it actually works for cooling / consistency. Any quirks?

You're right about the housing, looks like this: - http://dreamsofdrifting.com/ae86/waterinlet/

This is by no means my idea, I found out about it when i had my first coupe in 2008 and did it on that car as well (i just forgot which diagram i used back then which led me to create this thread). It's still relatively new on the current coupe, but I ran about 6 track days with the old coupe and the setup was perfect, fans kick on and off at certain temps (i don't know off the top of my head, but you can get different switches for different temps if i remember correctly) and had 0 cooling issues as far as water temps are concerned.

I liked it much better than the clutch fan or a manual switch. I'm currently using a 13" SPAL pull fan which fits right under the stock fan shroud. The only thing i'd keep an eye on are the fuses and wiring, using the wrong gauge wire could cause premature wear on fuses and fan failure, leading to potential overheating.

Here are links what i used:
-Fan: http://www.amazon.com/gp/product/B009OB ... ge_o07_s00
-Wire/Relay: http://www.amazon.com/gp/product/B003PB ... ge_o07_s00
-Relay: http://www.summitracing.com/parts/BCH-0332209150
-You can find the thermo housing & switch from your local pick a part, i bought a new thermostat & gasket from toyota just to be safe.

Does the water temp stay consistent in the middle of the gauge at operating temp and not move?

Any weird quirks when the fan kicks on like dimming lights or loss of power?

I'm familiar with the circuit. I also have a 92 t stat cover with thermo switch on my engine. I just never got around to trying the e fan. One thing I noticed about the relay kits is they usually come with a 25A+ fuse which is good if you need that much to run the fan, but I was worried that much extra current might be too much for the stock battery and alternator wire gauge. I'm not an electrical wizard though. I ended up grabbing a small fuse box (with pigtails) off an ae101 that houses 3 relays and 1 fuse. I planned on using a fan like this which flows decent cfm but doesn't draw a lot of amps: http://derale.com/products/electric-fan ... ple-detail

Now i see what you mean. No quirks or issues at all, temp stays in the middle (on the old coupe and the new), no loss of power or dimming of the lights either. It just kicks on when needed and shuts off without any hickups. I have two SPDT 30A relays with a 30A fuse, i used gold plated connectors to make sure electrical flow is consistent snd foesnt build/put strain on the fuse. The fan is a little on the loud side, but not louder than the oem clutch fan and it mives a good amount if air to help cool the water temp in a relativley short amount of time (stays on for about 30-60 seconds depending on weather/driving conditions).