Yo guys almost have my 95 SR figured out waiting on a Cam Position Sensor. Figured I might as well do something till then. So I busted out my chiltons and read the wiring diagram for the AC condensor fan relay and what not. How would be the best way to do the AC fan mod?

Theres a blue and white wire that has 12v 24/7 and the other one is black and blue and just a ground. Thats apperantly the one controlled by the relay.

I'd prefer for it to work when the AC comes on with out me making it also. If it wasnt for that Id just run 2 new wires to a switch and be done.

That's intersting. I was told that the circuit just needed to have switched 12v+ added to get the fan to run off a switch, while retaining the a/c/auto-on function. I will be following this one, as I want/need to add the ability to have the aux fan work off a switch when the a/c is off. That little fan really helps out! It's also an expensive bugger to replace if you can't find a junkyard one.

John B.

If the ground is switched, you could cut the ground wire you mention, solder in a wire going to a switch that is connected to ground and then heat shrink the soldered connection. Pretty easy to do, and you retain normal functionality of the fan while adding manual control.

HTH

Acknowledged. I didn't think it was ground switched, though, so this is news to me. Guess I'll have to haul out my voltage meter.

John B.

John, I don't know what the case is. I was just going off of what he stated in his post. Hope I didn't add any confusion.

The ground is switched. I work at an plumbing heating electrical shop, I'm off work and waiting for the electrician to get off work now. <img src="/forums/images/graemlins/lol.gif" alt="" />

BTW Ive also metered and read the Chiltons both say the ground is switched depending upon the relay

Add in another relay with the contacts in parallel with the existing one. then it's just a switch and you're set.

Walt, Ill call you for more info. The electrician I wanted to ask wasnt back yet and i needed to go home.

Maybe Ill make a nice write up on how to do this.

I've done this on my 91 but it uses switched 12v not ground.


This is a rough wiring diagram of what you can do if you want to use a relay and a switch.
85 Fused switched 12v or ground
86 Fused constant 12v or ground
30 A/C fan
87a Factory A/C fan wire
87 Ground

You can either used switched gound or switched 12v to activate the relay just keep in mind that if 85 is 12v than 86 has to be ground, and vice versa. Fuses are your friend don't be afraid to use them, the whole point of using a relay is so you don't draw a bunch of current through a switch, typically a relay is rated for 30 plus amps, when your $3 switch from the store can handle 15 or less amps. Also using a relay this way allows you to manually control the fan when you want to and also allow it to work automatically(factory).