What you need to do is go to www.bpg-inc.com and order up Bosch relay part # 0 332 002 150. From there, what you want to do is hook up terminal 86 to a switch in your car.(this wire does not need to be heavy gauge as it is only triggering the relay and draws only around 1A or so) The other end of that switch you need to pull from either directly off of the battery or from your fuse box. Terminal 85 will be connected to ground. Terminal 30 will wire directly to the battery using 10awg wire. Terminal 87 will connect to the + side of the fan (I can't remember which wire it is, but I know you want to connect your fan up using the outside two wires... leave the middle wire alone, it does not connect to anything). The - wire on the fan will connect to ground. You're all done!!! PM me or e-mail me if you have any further questions. It's entirely up to you, but if you wish, you can fuse the + between the battery and the relay and/or the + going to the fan from the relay with a 50-60A fuse. I would recommend it, but some do the fan installations without.

 

wow you had me up to order the bosch relay. what is all that terminal 85, 30 etc? and how much is this, there is no price on the kit?

now with this kit is the only other thing i have to buy a toggle switch? will this supply everything???

 

You'll need some 10ga wire to run from the pos side of the solenoid to the 12V in on the Bosch relay. Then on the 12V out run another 12ga wire to the power wire on the electric fan. If it's a GT fan, you will have a low and high speed wire. On V6 fans...both are high. Tie it in to the high speed wire. Then ground the black ground wire from the fan on something.

Now you need the signal wire to turn the relay on. You can use light wire for this. I tapped the 12V key-on source from the red power wire on the low coolant sensor. All you need is a tap, won't hurt the function of the sensor. Then i ran that wire to the signal in terminal on the relay. Then for the signal ground, i ran the wire back to the passenger compartment to a switch under my radio. the wire goes to the switch and then gets grounded. When you close the switch and complete the ground, fan goes on. Open it and it's off.

That's how i wired my SN95 fan.


I used to have a more complex method using an ON-OFF-Auto switch so i could use a temp sensor and also have a manual override....but i found that i just left the fan on all the time except when i was making a pass.

 

I have my fan wired using a off-hi-low switch on the dash, but I think I want to wire it in to a thermostat. Where can I get one that isn't going to cost my $70 like the Summit kit? Also, can people show me there brackets? I inxstalled mine on my Fluidyne (which I bought before the fan or I would have bought a SN-95 Radiator.) I have some pretty simple brackets but they are not exactly beautiful.

I can find my wiring diagram and post it on saturday if people are interested.

HTH,
Gabe

 

I think the relay was something like $22 or so if I remember correctly... call them up and ask. Anyway, I was looking at the schematic of the relay when I said that... all of the terminals are labeled on the relay itself... when you get it, you'll see the numbers and be able to hook it up exactly how I said.

You will need to get yourself a toggle switch, doesn't have to be anything special, it's extreemly low current, so almost any will work.

You will need the cabling... 10awg for the battery to relay, relay to fan, and then the ground on the fan. You will need 18-22awg for the relay trigger wire to go to the switch, and from the switch to your + source. Other than that, you are in good shape.

 

well i was just out looking at the fan, cleaning it a bit. the only electrical fitting on the fan is a plug fitting with three prongs in it. how do i wire to this?

 

You will only use the outside two prongs. One of them is the +, the other is the -. When you plug it in and start it up for the first time, it will either blow air foreword or backward... you will know then which is which, if it's blowing air the wrong way, then swap the power and ground leads and it will correct the polarity... don't worry, it won't hurt anything, it's just an electric motor. They can spin both ways.

 

The last elec fan install I did on a car that I had I just bought a fog light wiring kit from the local Canadian Tire. It came with the fuse/wiring/relay and the switch not to mention a wiing diagram for those who are mechanicly declined:lol: Worked great for me

Cheers
Paul

 

The SN-95 fan draws somewhere in the neighborhood of 50-55 continuous amps... there isn't a fog light relay that I know of that would be able to support that. I have tried many different 40A relays and such and they have all fried... that's why I have gone to the large 75A power relay... and has everyone else that has installed the Mark VIII and SN fan.

 

so i just solder the wires on the prongs then? then go from there?

 

You can either do that, or you can go the easier and in my opinion better way of getting the wire connectors to slip on the terminals. All you need are some 10awg female slip connectors. Go up to your local hardware store or your local auto parts store and pick up an assorted package of wire connectors... you'll see which ones you need in there.

 

o ok cool, if i have anymore questions ill let you know

 

ok got another, how do i use the two speeds of the fan? two toggle switches?? hmmmm???????

 

Most people don't... do you really want to? Is there a reason you want to? The high speed won't need to be on all of the time if you use an adjustable thermostat controler... again, those are cheap, a Hayden fan controler from Pep Boys is something like $20 or so and will do the job just fine, you can even still run a manual switch if you really want.

 

I've never dealt with that particular fan, but I thought it drew closer to 30 amps. What size fuse do you all use for this fan?

Also, you are putting a reverse-biased (that is, wired between 12V and ground so that it does not conduct) diode in parallel with the fan, across the relay contacts to prevent arcing when the relay opens, aren't you?

If not, that is probably why the relay is frying--what's happening is that when the relay opens, the fan is still spinning and acts as a generator, producing high voltages which will arc right through the relay contacts, burning them up.

The reverse-biased diode "shorts" out these high voltages, preventing them from damaging the relay contacts.

Do a google search for "diode motor arcing" and you'll find lots of references for this.

See http://groups.google.com/groups?q=m...=en&lr=&ie=UTF-8&safe=off&selm=1992Jul9.113918.5785@csc.canterbury.ac.nz&rnum=1

for some more information and a diagram (at the bottom of the post)

Factory fan relays probably have the diode built in.

The SN-95 fan draws somewhere in the neighborhood of 50-55 continuous amps... there isn't a fog light relay that I know of that would be able to support that. I have tried many different 40A relays and such and they have all fried... that's why I have gone to the large 75A power relay... and has everyone else that has installed the Mark VIII and SN fan.

 

i just thought it would be good to run the high speed. if i dont have to then ok.

so let me get this whole setup strait. ill get the Bosch relay kit mentioned earlier, and a toggle switch to hook the fan up? will this be the best way, does this kit include a big enough relay?

now is there any better ways that anybody with a sn95 fan has done??????????

 

i just thought it would be good to run the high speed. if i dont have to then ok.

I have a V6 fan, so all i have is high speed.

I've had my car out recently on a day that was 101 degrees. Sitting in traffic in a black car with the A/C on the temp needle never rose above normal. That's with a 3-core pep boys radiator and a new Bosch Water pump and my underdrive pulleys' removed for the summer for just this reason.

 

so anybody else with a sn95 fan set up?

 

Like I was saying mine is completely switch controlled. I have a three position switch, OFF/HIGH/LOW usually the fan is set on low, if the car is getting warm (not often I will switch to HIGH,) I can also switch it to off for any time that I might want the key on and the fan off. I bought a simple looking flush switch from Radio Shack and painted the red part with flat black Testors model paint. It may not look stock but it does blend in and looks better than a big chrome toggle sticking out of the dash.

HTH,
Gabe

 

hey GBX i would appreciate it if you would give me that diagram and detailed instructions for your off/hi/low switch setup. thanks a lot!! i like what youve said so far

 

so anybody else with a sn95 fan set up?

Try this website. I think I will be trying the two speed setup on my '91...

http://www.geocities.com/smithmonte/Auto/MarkVIII_Fan.htm

 

isnt that site all about Mark VIII fans though?

 

isnt that site all about Mark VIII fans though?

Yes, but the instructions can be applied to any fan. What are the advantages of the SN95 fan over the Mark VIII fan?

 

I will pull out my wiring diagram when I get to PA this evening (that is where I am working on my car) but I may not be able to scan it to post until sunday afternoon when I get home.

Something to note though if you have a aftermarket radiator the fit might be tight, I have less than an inch between my SN-95 fan and my water pump pulley with my Fluidyne.

Gabe

 

i have a 3 core modine radiator