I'm planning a radiator replacement and electric fan install on my E36. Have a ton of parts waiting in the garage but I've never done wiring and don't want to butcher the fan install or my existing wiring in the process.
What are some good online resources you might recommend so I can embark on a crash course for automotive wiring?
Adding a fan or just replacing an existing fan? If replacing, YouTube would be fine. If adding, maybe get some kind of basic wiring book, a few YouTube videos, and a vehicle-specific service manual with wiring diagrams.
Electricity is like water.
Amps = flow
Volts = pressure
Watts = how much water you move.
If you have the task of filling a 5 gallon bucket in 2 minutes, you can get there with a tiny hose and a lot of pressure, or a huge hose and very little pressure. Your voltage is fixed at 12v (like having a fixed water pressure) so your amperage (flow) will have to be supplied by an adequately sized wire.
Find the amp draw of the fan and consult a google chart for "amperage gauge wire" or something. It will show you how a 10-ga wire can handle 30 amps at 5', 25 amps at 10'... etc.
You'll likely be using a relay. A relay is simply a remote switch. Of the four pins, there are two that take battery power in the big wire through to the fan. The other one is the switch side. When one side has power and the other has ground, it energizes the switch and sends power to the fan. In this way you can configure it in many ways to tell it when to come on. For instance, I added a daytime running light circuit but I only wanted it to be on when the engine was running (not just key-on). I grounded the switch side of the relay through the oil pressure sensor. Engine running, oil pressure happens, grounds the wire, turns on the relay, lights come on.
Lean on us, we'll get you set up.
Watts = volts x amps.
Let's say you screw in a 120w light bulb in your house. 120w = 120v x amps. In this case, you're using 1 amp. Put a 120w bulb in your car and it will look like this: 120w = 12v x amps... the same 120 watts will need 10 amps. In the water analogy, the first example is like the small hose/big pressure and the second example is the big hose/small pressure. To do the same amount of work in your car, you need a bigger wire (hose) to get things done.
This guy has one of the best tutorial sites that I have seen anywhere.
I train new aircraft techs in electrical and electronics troubleshooting and will refer to a few of his tutorials for soe basic knowledge stuff for the guys.
This has been done a thousand times and thoroughly documented on bimmerforums. I would read through a couple of DIYs and watch a YouTube our two and jump in!
Be careful that your fan mounting technique doesnt damage the radiator and that nothing can contact the fan blades which will blow the fuse and cause a potential overheat. Also, if you havent bought a radiator, think about a thickened z3mcoupe knockoff on ebay. Race an lsswap e36 and this radiator keeps the v8 even cooler than the stock i6 used to run. Also strongly consider an e30 coolant reservoir (self bleeding). Love mine!
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Spal Electric Fan Conversion DIY
In reply to Curtis73 :
Really appreciate the explanation about the relay, that was super helpful!
In reply to VegasNick :
This looks like a great resource for the conceptual foundation. Thank you!
Curtis73 said:Electricity is like water.
Amps = flow
Volts = pressure
Watts = how much water you move.
this is mentioned so much around here and is so simple and accurate, I put it in my sig for future copy paste.
In reply to VegasNick :
This looks like exactly what I needed! Thanks!
_ said:Curtis73 said:Electricity is like water.
Amps = flow
Volts = pressure
Watts = how much water you move.this is mentioned so much around here and is so simple and accurate, I put it in my sig for future copy paste.
Perhaps I should clarify, though, and mention that electricity and water don't MIX well.
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