A/C Condenser Fan Switch

[outono]

Im looking to put a switch in my D1 to run the condenser fans without the condenser running. I've read this can be done by putting a switch on the ground at 87 (black / brown wire) on the K109 relay. Does this sound correct? If done this way, does this mean I need to flip the AC on and hit the switch to defeat the condenser?

Ideally, i'd like to just flip a switch and get the fans going, nothing more. Can someone with much better electrical knowledge shine some light on this?

[EDIT: diagram below is not for a V8. See below for the correct information]

 

[1of40]

Yes, I ran a wire from a toggle switch to the relay and from switch to a grounding point on my dash in my NAS90.

 

[94Disco1]

No need to flip the A/C switch on for this mod. Basically by grounding the 87 side of K109 you are mimicing the signal that the consenser fans would get if the A/C switch was on.

I had one of these carling switch mounts already https://www.shapeways.com/product/BQFD8MQ86/land-rover-discovery-carling-switch-bracket
So just installed a switch like this one https://www.otrattw.net/contura-x-engine-fan-sealed-rocker-switch-green-lens-V1C1JXX1-10L9B-57T.html

One wire is soldered 87 on K109 and runs from the relay up to the switch (switch is normally "off"). Second wire goes from the switch to any ground point (pick a bolt behind the dash as long as you verify it is chassis ground with a voltmeter).

When you flip the switch "on" it connects the car chassis ground to 87 on K109.

If you want to get fancy with the switch shown above, you can also add a backlight feed. For this would need to pull from the variable backlight wires that go to the clock, radio, HVAC switches etc.

One thing to remember is that the fans will only come on when the key is in the ACC (or maybe on?) position. So won't turn the fans on when truck is turned off.

Good luck!

 

[94Disco1]

Photo attached in case it helps?

 

[p m]

Run a switch from the pin 1 of X113 (fan switch) to the ground, or, if you want to keep all the wiring inside the vehicle, to pin 86 of relay K109 (in the right footwell). I would not run a switch to the pin 87, because you will be carrying about 25 amp through that switch.

 

[Greg_M]

I used a Powerwerx ITS-12 relay timer to provide a circuit independent of the factory wiring. It's been working well. Useful if you want to power other accessories (vhf/ham radios for instance) on separate circuits as well (through an auxiliary fuse block in my case).

 

[DiscoClay]

Which relay, in the right (Starboard footwell? Got a pic?

 

[outono]

 

[p m]

That yellow relay. It's a bitch to get to, you need to undo the nut that holds the panel (13mm or 1/2"), lower the assembly, and get to the relay and its connector.

 

[94Disco1]

Thanks p m for correcting it is not 87. Are you sure it’s 86 and not 85 though?

 

[p m]

Thanks p m for correcting it is not 87. Are you sure it’s 86 and not 85 though?

Going by the Rave circuit diagram posted here, switching 85 of K109 to the ground will result in a blown fuse.

 

[Icannap1]

You need to ground pin 86 on the relay that will activate the relay.

 

[special ed]

You guys are making my head hurt looking at the relay. Now im going to have to go look at Annabelle and see what color code wire i Switched to ground so i could turn on the fan when towing and climbing hills. I found a write up years ago and just tapped in a rocker switch on the wire.

 

[special ed]

So i went and looked at Annabelle because this is nothing new, this mod has been around for a long time. Scotch lock (dont cut the wire) onto the green white stripe wire off the relay, add a switch and run the other leg to ground. You dont have to worry about switch being on when ac is on since it is a ground leg. basically the relay is grounded to turn on the fan. they have a constant 12v feed going to the circuit.

 

[outono]

So i went and looked at Annabelle because this is nothing new, this mod has been around for a long time. Scotch lock (dont cut the wire) onto the green white stripe wire off the relay, add a switch and run the other leg to ground. You dont have to worry about switch being on when ac is on since it is a ground leg. basically the relay is grounded to turn on the fan. they have a constant 12v feed going to the circuit.

Thanks Ed. So G/W wire looks like 85 on the relay, NOT 86 as suggested (although maybe either would work?)

 

[p m]

Thanks Ed. So G/W wire looks like 85 on the relay, NOT 86 as suggested (although maybe either would work?)

The circuit diagram posted earlier shows G/W wire carrying +12V from the fuse panel. There's a good chance Ed had modified something in the wiring earlier, or the wiring harness doesn't match the circuit diagram.

It is easy to check, though. Pull the relay and turn the ignition ON - don't attach the switch to any wires carrying +12V.

 

[outono]

It looks like the diagram I posted earlier may be from an TDI MFI.

Here is the SFI-V8 diagram

 

[p m]

OK, between Rave and Ed, Ed wins every day.
However, your first circuit diagram was not for TDi, either.

 

[outono]

OK I did this today. It's wildly easy, but of course I tapped the wrong wire initially, which got molten hot instantaneously. Luckily I was babysitting it and managed to stop anything before it got out of control.

For those reading this later, the relay is tucked inside the metal relay holder underneath the glove compartment (has 2 green relays and 3 yellow ones). It is not on the passenger kick panel.

To tap the relay wire, I used a Posi-Tap, which tends to preserve the integrity of the wires. I never have good luck with Scotchlok.

I used the ground underneath the passenger seat since the ground on the kick panel is always getting wet from a leak when it rains. That ground takes a #6 nut.

Simple as can be, although somehow I managed to trip the inertia switch when I whacked my hand tucking the relays in.

Word of caution: the fans will turn on even if the truck is shut off so don't forget to turn off the switch...