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Oh, Herro!
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Discussion Starter #1
Following my concept of modding anything and everything I can get my hands on (especially if it's cheap), here's a question for all you electrical gurus:

I want my fan to be on all the time, which is what it does right now since the thermostat is busted. The fan is controlled by a relay, so I'm assuming that I could rewire the relay so that it's on whenever the car is. I also would like to be to run the wiring to a switch, independant of the ignition, that would allow me to run the fans with the car off. I'm hoping that I can do a similar wiring trick to get that to work.

The problem here is that I know basically nothing about relays and how they work. I have a general idea of the mechanics of a relay, but the wiring is another issue. So here's where you come in. Explain the basics (read: which terminal on the relay to play with and how to wire it so I don't break it) and I can take it from there.

Just in case your wondering, my logic for this mod, is that I have noticed serious heat wash on long trips since the installation of my WAI, so I want that fan on all the time. Also, as I become more and more interested in taking the car to the track, what better way to help keep the engine cool between runs than letting the engine's own cooling fans do the work?

Thanks in advance, guys!
 

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Boost anyone?
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1,625 Posts
I know it is possible to have the fan switched operated as well as when it is off. It started when i was looking for a wire to tap into for my windshield washer turn signals. I tapped into a wire and the fans turned on. It was weird, i thought nothing of it at the time but I thought i would just let you know. Im sure if you ground the wire and connect it to a switch you can do it. Now the question is, can i find which wire it was??
 

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Your electrical friend
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2,177 Posts
Samo, or anyone else reading this hit me up an e-mail and I'll tell you how to do it. There's lots of ways to do it, but only a few of them are the "right" way IMO. The biggest issue is that the fan relays probably don't have power with the ignition off, and they are trigger by a ground input wire from the ECU. So we'll need to route power to the relays as well as ground them. When doing this we have to be carefull to protect the electrical system from backfed current using a few diodes. Eventually I'll do a write up about this when I do this to my car, maybe I'll do it now since I'll be doing it to help you guys out. I'm going to use a timed relay to keep the fans and an electric water pump running for a few minutes when the car is off, and there will be overrides for both when waiting in line at the track. I'm also going to consider an electric oil pump with cooler. That way when your car is off or you override them, your fans will continue to cool down the engine via the oil and coolant as they are pumped through their respective radiators for a few minutes. I'll start figuring it out when I get home and can look at my FSM. Should be fun.
 

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Oh, Herro!
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2,337 Posts
Discussion Starter #4
Actually, I would be very interested in both mods. When you get it figured out, post it up or do a write-up for NPM! My electrical knowledge is limited (didn't even think about diodes...), so your help is much appreciated!
 

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Your electrical friend
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2,177 Posts
I've been thinking that if we had an Electrical forum it'd be cool, and I wouldn't mind helping moderate it. I've moderated a different forum for over a year now of a completely different subject matter. Another good mod for it would be Probedude, he knows a lot about this kind of stuff. Maybe I should run this by someone. Mike Young perhaps?
 

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Oh, Herro!
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2,337 Posts
Discussion Starter #6
Talk to Scott - he's pretty much in charge around here.
 

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freakish poster
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1,236 Posts
Don't forget though that running those fans cost HP. I don't know about y'all, but when my fan kicks in the idle momentairly dips down due to the alt load.
 

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Oh, Herro!
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2,337 Posts
Discussion Starter #8
My idle drops a little - but not much, and then it's back up again. The fans are electrical, not mechanical, so there should be no HP cost involved.
 

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freakish poster
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What are you talking about? Do you mean it cost nothing (in HP) when there's a load put upon the electrical system? Yes, it's only a marginal amount but it's ludicrous to say that the fan dosen't put a load on the engine (again, yes a marginal load) and that to run the alternator and charge the battery is "free." The load for sure is no more than 1 or 2 HP but yes granted the electrical fan runs more efficiently than a mechanical fan.
 

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Your electrical friend
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Calling all autos!

Hey Samo, is your car an Auto? I need someone with an automatic to do a few tests for me so I can finish this write up. The fans in automatics have two coils, one for low and one for high speed, and there are seperate relays to run each coil. What I need to figure out is if when the fans are on high, does it use just one coil or both. I also need someone with an Automatic SE-R to do the same tests likely. Let me know. Thanks. I'm going to solicit some help in the SR20DE area to see if someone can do the auto SE-R tests for me. :)
 

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Oh, Herro!
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2,337 Posts
Discussion Starter #11
Centurion said:
What are you talking about? Do you mean it cost nothing (in HP) when there's a load put upon the electrical system? Yes, it's only a marginal amount but it's ludicrous to say that the fan dosen't put a load on the engine (again, yes a marginal load) and that to run the alternator and charge the battery is "free." The load for sure is no more than 1 or 2 HP but yes granted the electrical fan runs more efficiently than a mechanical fan.
I suppose you're right - but it's not something I'm overly worried about. I want to have it on a switch so I can shut it off if necessary.

And no, luckily, my car is a 5-speed.
 

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Your electrical friend
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2,177 Posts
Well Samo, I've yet to complete the write up, as I want it to be "complete" and I need to verify the fan operation of Automatics. But, I have enough for people with manual cars to do it.

Ignition Independent Fan Override instructions for:
1993 GA16DE/SR20DE with Manual Transmission

The following instructions allow you to override your fans so they will operate continuously with the ignition off. There are various benefits/drawbacks to this. If you want to override your fans only when the ignition is in the on/start position, please use the Ignition Dependant Fan Override instructions.

The relay you’re going to manipulate for the override is referred to as Radiator Fan Main Relay and is located in the relay box just left of your battery. The relay has 4 wires, black/white, blue, white/green, and brown/white. You simply need to get the power that is present in the black/white to the brown/white wire. You can’t just trip the relay, because the relay has neither ground, nor voltage present at it’s two respective coil wires, blue and white/green. In my opinion, to operate the fans without putting the rest of the cars electrical system at risk, simply install another relay to jumper power from the black/white wire to the brown/white wire. A 12V 20/30A SPDT (Single Pole Double Throw) or SPST, (Single Pole Single Throw) relay with socket will be required to do so. Either one will work, so use whatever is cheaper. If you buy the SPDT you'll want to pull the 87a terminal and wire lead out of the socket. Now, there are various ways to attach the wiring, however, there is only one method that I am going to mention, as I think it is the most correct method. With the positive battery terminal disconnected, remove the fan relay from the relay box. Now release both the black/white and brown/white terminals from the harness/socket. (Make sure you remember which goes where). A small, straight metal pick works well for these kinds of things. Carefull soldering should allow you to just solder a wire lead to each terminal and reinsert the terminals back into the harness, making sure they lock back in. When I say solder them to the terminal, I mean to solder the leads to the flat area where the OEM wire is crimped into the terminal. I would also coat each terminal with dielectric grease before reinserting them, do the same with the leads for the relay socket. Now Solder one the lead coming from brown/white to the number 87 terminal in the relay socket. Using an IN4004 diode, solder the anode end along with the black/white wire lead, into terminal 30 of the relay socket. Solder the cathode end of the diode (Identified by a silver band) into terminal 86 on the relay. Now, terminal 85 is where you’ll connect the wire that runs all the way to your dash mounted override switch. One side of the switch will connect to that wire and the other will go to ground. If you purchased a lighted switch, then you’ll need to find a source of power for the light. Assuming you're going to have the switch mounted somewhere near your steering column, you can tap into an ignition wire that is hot when the key is off. To do this, I'd recommend carefully cutting back the insulation and soldering a wire lead to the wire and then covering the joint with electrical tape. Now, just coat each terminal of the relay with dielectric grease and slide it into the socket. You can mount the socket onto the relay box bracket with a short screw or a cable tie. Most relays have a mounting tab with a hole in it for this. Now hook your battery up and test to make sure everything works ok. The fans are still protected by the fusible link located in the fuse, fusible link, relay box located to the right of the battery.

Ignition Dependant Fan Override instructions for:
1993 GA16DE/SR20DE with manual transmission

The following instructions allow you to override your fans so they will operate continuously as long as the ignition is in the on/start position.

The relay you’re going to manipulate for the override is referred to as Radiator Fan Main Relay and is located in the relay box just left of your battery. The relay has 4 wires, black/white, blue, white/green, and brown/white. When the ignition is in the on/start position, the relay has power and only needs to be grounded to operate. To do this, you’ll run a wire from a dash mounted switch to this relay. With the positive battery terminal disconnected, remove the fan relay from the relay box. Now release the blue wire terminal from the harness/socket. A small, straight metal pick works well for these kinds of things. Skillful soldering should allow you to just solder your wire lead to the area where the blue wire is crimped to the terminal, then reinsert the terminal back into the harness, making sure it locks back in. I would also coat the terminal with dielectric grease before reinserting it. Also coat each terminal of the relay with dielectric grease and reinsert it. One side of the switch will connect to that wire coming from the relay and the other will go to ground. If you purchased a lighted switch, then you’ll need to find a source of power for the light. Assuming you're going to have the switch mounted somewhere near your steering column, you can tap into an ignition wire that is hot when the key is off. To do this, I'd recommend carefully cutting back the insulation and soldering a wire lead to the wire and then covering the joint with electrical tape. Now hook your battery up and test to make sure everything works ok.

Something I'd highly recommend to anyone considering doing numerous electrical modifications, is to connect a length of 10 gauge minimum, 8 gauge maximum, wire to the battery terminal, protected by an inline fuse holder near the battery. It's not easy, but run this wire through the hole to the right of the battery, where the harness goes through to a large rubber grommet on teh firewall under the dash. Run your new wire to a barrier strip or an aftermarket fuse block. Using a sheet of brass or copper, fabricate a buss strip to be attached to all terminals on one side of the fuseblock or barrier strip. Now you'll have a safe source of power for numerous future electrical modifications or added circuits.

If anyone ever wants help with electrical modifications of any kind please feel free to e-mail or pm me, I'd be glad to help. :)
 
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Running Fans

Hey this is a handy and EASY trick. All you have to do to run your fans continueously is this. Go into your Relay box and pull out your A/C relay. Then with your climate control click on the A/C compressor switch(the blue one) and turn your cabin fan on between levels 1-4. When your A/C is operating the fans will run. So when you pull your relay your A/C compressor will not engage, but your fans WILL run non stop. When you want the fans to stop then simply click off the A/C button or turn the cabin fans off. ON a real hot day if you want A/C again just simply put the A/C relay back in. It's simple and it works, I've been doing this for a while and it's a great trick for the dragstrip. If you have any questions E-mail me.
 

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Oh, Herro!
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2,337 Posts
Discussion Starter #14
Well holy crap! Nice write-up, I appreciate it!
 

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Your electrical friend
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2,177 Posts
That's an awesome trick Smoke, thanks! I'll likely do that one myself until I put in electric oil and water pumps.
 

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Please Shift Here
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6,696 Posts
cool, I wanna try the one that lets the fans run with the ignition off. few things. Will this work on a 97 auto? also, does it really do that much good if the coolent isn't flowing, don't you need the water pump going when the fans go to make sure the coolent gets to the engine?

The oil cooler with the oil pump sounds like a good idea too especialy for those people with turbos. You should do a write-up on getting the oil to continue flowing with the fans cooling the oil cooler.
 

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Your electrical friend
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2,177 Posts
Originally posted by: 1997 GA16DE
"cool, I wanna try the one that lets the fans run with the ignition off. few things. Will this work on a 97 auto? also, does it really do that much good if the coolent isn't flowing, don't you need the water pump going when the fans go to make sure the coolent gets to the engine?

The oil cooler with the oil pump sounds like a good idea too especialy for those people with turbos. You should do a write-up on getting the oil to continue flowing with the fans cooling the oil cooler."
I wanted to do the write up to include automatics, but I haven't had anyone with an automatic offer to help me to do the write up. If you're willing to work with me via e-mail we can get it figured out for your car.

I plan to run and electric water pump when I put a DET in, and it will help a lot then. It does help some even with a mechanical pump, even though the motor isn't running. I think a lot of guys just want their fans to run all the time when they're at the track, car on or off.

I'll do the write up on electric oil pump and cooler when I put the DET in and do those same mods. The nice thing about the electric oil pump, is that you can wire it to turn on when the key is in the on/start position so you'll have 100% oil pressure when the car starts, and that's a very nice feature to have. I'll do write ups on overrides for the whole thing as well as an alternative to turbo timing, which will be to install a timed relay to keep electric water and oil pumps running as well as the fans to cool them when they're running through their respective radiators.

Anyways, drop me a PM or e-mail and we'll get your override figured out.
 

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samo, you dont think the power gained from your "cooler" engine bay will be offset by the extra strain on the electrical system w/ the fan being on?
 

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Your electrical friend
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2,177 Posts
samo, you dont think the power gained from your "cooler" engine bay will be offset by the extra strain on the electrical system w/ the fan being on?
I think the point of the fan override is to keep things cool when the car is not running down the drag strip. I think most guys let their fans run in regular mode when they get up to the tree. Beside that, unless the ECU cuts the fans at WOT, if the engine is hot enough, it's going to run the fans whether you like it or not. As far as electric water and oil pumps go, the electrical drain put on the alternator is less of a HP loss than mechanical pumps. I don't know how much drain people think a charging alternator places on an engine. A low load charging alternator versus a high load charging alternator are not similar to the engine drag placed by an A/C clutch when it's not engaged versus when it is. Alternator resistance doesn't change significantly between high and low loads, not significantly enough to undo the gains of electric pumps.
 

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Please Shift Here
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6,696 Posts
toolapcfan said:
I wanted to do the write up to include automatics, but I haven't had anyone with an automatic offer to help me to do the write up. If you're willing to work with me via e-mail we can get it figured out for your car.
I'd love to work on it, but for now, my normal computer has crashed so I'll be pretty busy with that. plus with me at UCF, I have almost no time anymore to tinker with my car. I'll try to see if this method works or what needs to be changed. I might wait for now snce I'm too planning on a DET swap
 
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