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?
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??
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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Rob '93 SE-R
PM or e-mail me for Progress swaybars $190 shipped, B13 Progress coilovers $1300 shipped and B13 Progress LCA brace $160 shipped.
Last edited by toolapcfan : Sep 20th, 2002 at 11:01 AM.
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!
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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Rob '93 SE-R
PM or e-mail me for Progress swaybars $190 shipped, B13 Progress coilovers $1300 shipped and B13 Progress LCA brace $160 shipped.
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.
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.
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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Rob '93 SE-R
PM or e-mail me for Progress swaybars $190 shipped, B13 Progress coilovers $1300 shipped and B13 Progress LCA brace $160 shipped.
Originally posted by Centurion 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.
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.
__________________
Rob '93 SE-R
PM or e-mail me for Progress swaybars $190 shipped, B13 Progress coilovers $1300 shipped and B13 Progress LCA brace $160 shipped.
Last edited by toolapcfan : Sep 23rd, 2002 at 09:46 PM.
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.
Fan modifications...
Linear Mode
