How to: Windshield defroster on a switch

[migit]

Was almost done writing this up in detail and hit a thumb button on my mouse going back a page and deleted everything. So I'm gonna make this brief.

Simple way to setup your windshield defroster to be controlled by a switch. This is being displayed on a s13, diagrams will reflect there of. Obviously this is only useful if you believe AC consists of rolling your windows down, and the only time you really use it is to defrost your windshield in the morning.

I'm sure theres a better way to go about doing this, this works for me. You'll notice I'm keeping things simple throughout, call me lazy... but it works.

Here are the schematics for how I did it. For most of you this is enough, can figure the rest out on your own.

Start with...
http://img69.imageshack.us/img69/2788/240sxac.gif

How I set it up...
http://img509.imageshack.us/img509/4776/240sxac3.gif

Pretty simple... Blower motor speed is controlled by the amount of amps being supplied to it. You need continuity between terminals 23 & 24 for full blast.

Before you start, Make sure your climate control is currently on windshield. Once you disconnect your push control unit you wont be able to adjust the position its in.

Remove your Dashboard, heres a tutorial if you haven't done this before: s13 Dash Removal: 240sx Articles: Nissan Forums / Infiniti Forums - NICOclub (http://forums.nicoclub.com/zerothread/228752)
http://img140.imageshack.us/img140/9797/img1102a.jpg

This is the harness connected to the fan switch (on the push control unit) that we'll be working with...
http://img69.imageshack.us/img69/9885/img1108y.jpg

Should be obvious, but heres where it connects...
http://img140.imageshack.us/img140/152/img11142.jpg

The blower motor speed is dictated by how many amps is supplied to it. Depending on the fan switch position, each terminal has a different number of amps. Position 4 (Terminal 24) = ~13amps, position 3 (Terminal 25) = ~8amps and so on... I think position 1 was ~3amps. The more amps, the harder she blows... heh.

You can see this here...
http://img97.imageshack.us/img97/4319/img1109z.jpg
http://img684.imageshack.us/img684/2552/img1110l.jpg

You can set yours up how ever you want. I decided to not destroy the wiring harness, cut any wires, or do any soldering. Instead I found 2 male connectors that fit into terminals 23 & 24 on the wiring harness. To these connectors obviously the wire to be ran to your switch. For added protection I threw in a 15amp fuse after the switch.


You need a switch that is rated for atleast 15amps and thick enough wire to be practical for this. Not sure what I used, its probably 14ga wire.
http://img69.imageshack.us/img69/8808/img1111z.jpg
http://img262.imageshack.us/img262/1499/img1112t.jpg

Gave everything a good tape job... Probably be annoyed later on when its a sticky mess.
http://img509.imageshack.us/img509/3355/img11143o.jpg

Now install your switch and your almost done.

To completely disconnect the push control unit, disconnect the other wire harness connected to it. And your going to need to either snip off the wire (controls temp) or remove it as shown.
http://img684.imageshack.us/img684/2713/img1115o.jpg

http://img31.imageshack.us/img31/8765/img1117n.jpg
Ziptied on that red line showed will lock temp control cable in hot position. Hot is all the way left, cold right.
http://img121.imageshack.us/img121/7929/img1121i.jpg


Tuck everything away nicely and you've got your windshield defroster now controlled by a single switch, with out destroying to much, or stripping alot. You can remove additional tubing for the AC as I did, and where the push control unit was you can now fill with what ever you like.


Pretty simple, if you have a better way to go about doing this or details to add go ahead and comment so everyone else can know. I know theres probably a better way out there to do it. This is what how I set mine up for now.. I'm sure I'll go more indepth later on.

[g6civcx]

Your 15A fuse is useless because the motor is already fused for 15A.

You could have just ran the Blue/White wire to the switch and then straight to ground.

I also hope you figured out how your water cock control rod and temperature control cable work.

[migit]

Your 15A fuse is useless because the motor is already fused for 15A.

You could have just ran the Blue/White wire to the switch and then straight to ground.

I also hope you figured out how your water cock control rod and temperature control cable work.

I ended up taking that fuse out.

The blue/white to the switch, switch to ground? I'm a visual learner, not sure if I understand. Any ground, or a specific?

The temperature control cable is locked in the hot position with the zip tie I showed. Not sure which rod that is, unless its the one that I showed I ziptied thats linked to the temp cable.


I might go back through and redo it, gut more if I can. Then I'll update this post. Thanks for the help.

[yukon]

Nice pics. Glad to see someone contributing something positive. And your hands are actually symmetrical which seems rare these day.

[g6civcx]

Battery to 15A fuses to Blue/Red wire to blower motor to Blue/White.

Take the Blue/White wire and connect to one pin on your switch. Put another wire on your switch and connect straight to ground.

It doesn't matter what ground. Just make sure it's a good ground.

And use the same or thicker gauge wire as the Blue/White white on the blower motor.

[migit]

Nice pics. Glad to see someone contributing something positive. And your hands are actually symmetrical which seems rare these day.

Haha, total creeper comment. But thank you lol.

Battery to 15A fuses to Blue/Red wire to blower motor to Blue/White.

Take the Blue/White wire and connect to one pin on your switch. Put another wire on your switch and connect straight to ground.

It doesn't matter what ground. Just make sure it's a good ground.

And use the same or thicker gauge wire as the Blue/White white on the blower motor.

I tested it out after your first response and forgot to post up my findings. If its not a good ground it doesn't blow very hard, woops. Good info now for anyone who wants to do the same. Just got to read through, thanks g6civcx.

[g6civcx]

I'm not sure exactly what you're trying to do with this.

If you need space savings, you could go with a full standalone Vintage air unit. It's smaller than the stock unit.

When you're on the track, sometimes you need to blast the heater to help cool down the engine. Having the position set towards the windshield could fog up your visor/goggle, especially on a really humid day.

I would tend to set the position to Feet and blast the heater that way.

Just keep that in mind.