Auxillary Fan Override Switch Write-up *pics* - Page 11

dlane2155 · 04-06-2010, 08:10 AM

Quote:

Originally Posted by gmelton2

dlane 2155,

I want to make sure I understand this, you say if I power the wire going to the relay terminal that you have circled in red, that will power the the A/C fan. Is this correct? Will I be powering the A/C relay or suppling power to the fan itself?

Thanks,

Greg

That is correct. I am going to do this in a few minutes to see how it will work, with starting up and shutting down. As I had an issue shutting down when I jumped the relay to make the fan on all the time. I will let you know how it all works out. I will take some pictures too. But the one I circled has continuity the fan power side of the connector.

dlane2155 · 04-06-2010, 02:21 PM

Quote:

Originally Posted by gmelton2

dlane 2155,

I want to make sure I understand this, you say if I power the wire going to the relay terminal that you have circled in red, that will power the the A/C fan. Is this correct? Will I be powering the A/C relay or suppling power to the fan itself?

Thanks,

Greg

Alright I could not get this to work the way I wanted without the jeep acting very funny when shutting down. I personally wanted to wire the fan so it only works when the ignition is on, and every wire I did that from was making it act weird. So here is my setup.

First I took apart the fuse box.

Then wired this wire to one end of the toggle switch. The other side of the toggle switch to a chassis ground.

Now because I wanted a lighted switch to tell me when I had the fan on and could not get a switch to do that, I bought an indicator light that will tell me whenever the fan is on. It will light from me activating the fan or any other source activating the fan. I tapped into the blue wire and ran this wire to one end of the indicator light, the other end of the indicator light went to a ground. Oh because the blue wire is so large and the other wire is so small, I used a yellow connector, and doubled over the smaller wire.

Off...

On

Alright, I don't know where you tapped into the blue/pink wire, but I would say if you did it near the computer, then try the way I did, and see if you still get the code. If you still get the code and do not care if the fan will run with the key off or on, then wire it from a constant 12V power, into the blue wire that I tapped into with the yellow connector. Of course I recommend starting and shutting the jeep down with it wired up temporarily to make sure nothing acts funny. If all works good, then hard wire it. I would try using the constant that leads to the 40 amp fuse that is for the cooling fan.

USMC_XJ · 04-06-2010, 03:09 PM

Quote:

Originally Posted by dlane2155

Alright, I don't know where you tapped into the blue/pink wire, but I would say if you did it near the computer, then try the way I did, and see if you still get the code.

That wire goes from the PDC to the PCM. Whether it is by the PDC or by the PCM does not matter.

Glad you got it to work though.

gmelton2 · 04-07-2010, 08:40 PM

dlan2155,

What color wire did you tap into? I cannot tell from the picture.

Thanks,

Greg

dlane2155 · 04-07-2010, 08:44 PM

Quote:

Originally Posted by gmelton2

dlan2155,

What color wire did you tap into? I cannot tell from the picture.

Thanks,

Greg

For the fan switch, blue/pink. For the indicator light, the big blue wire. Both lead into the cooling fan relay.

utah29er · 04-13-2010, 08:28 PM

Finally getting around to doing this on my 99 but ran into an issue...
PO had wired a thermostat to the the aux fan, which I removed, so now I need to re-establish the computer's control of the aux fan. I've got one ground and one power wire from the aux fan, and no idea how to connect them back to stock.

Can anyone tell me if this is the connector that goes to the aux fan in stock config?

thanks in advance

corndogduff · 04-14-2010, 02:58 AM

^ that's the plug for the fan, alright.

utah29er · 04-14-2010, 08:45 AM

Thank you McDuff.

Now I may proceed!

I'm going the simple switch/diode route.
CEL, here I come

dvmeter · 05-06-2010, 08:00 PM

I finally got around to doing this mod to my jeep. LOVE IT! I kept putting it off, and the weather started getting warmer and warmer and then I learned that something is wrong with my jeep in the wiring or pcm or something when it comes to the aux fan, bc it wasnt coming on, but the fan itself was good. If i unplugged the CTS on the thermostat housing while engine was running, the fan would come on. weird. So i just wired up a switch and comes on when i want it to, which is the way i wanted things anyways.

For those interested in a lighted switch, I just went to autozone and got their basic lighted switches (Dorman Conduct-Tite blue glow rocker 20 amp interuptor switch) part number 85922. Its very basic but it lights up when activated. I only had to use two of the connectors on the back too. The blue/pink wire got sent to the 12v/on or whatever it said, and I used a quick splice to tap into the cigarette lighter ground for a ground and it works like a charm. Lights up and activates fan when key is forward, vehicle doesnt even have to be on.

Oh and one other thing, I was wondering about this when I first read this. Nobody really mentioned how they ran the wires through the firewall. Maybe everybody else already knows a good way to do this, but I didnt. What I did was make a small hole in the gromet that goes around the hood latch cable. And pushed the wire through there. I know that that is kind of a techty spot, on my mom's jeep. she had some KC lights wired up years ago and then the vehicle always leaked when it rained. Turned out that gromet was gone, fell out or was taken out by installers and water just ran in there. So if you go that route, just make a very small hole so the gromet is intact or use some silicone or something.

Well thats how I did it. Works great for me. Now I just need some hood vents.

Muddeprived · 05-06-2010, 09:14 PM

Quote:

Originally Posted by dvmeter

I finally got around to doing this mod to my jeep. LOVE IT! I kept putting it off, and the weather started getting warmer and warmer and then I learned that something is wrong with my jeep in the wiring or pcm or something when it comes to the aux fan, bc it wasnt coming on, but the fan itself was good. If i unplugged the CTS on the thermostat housing while engine was running, the fan would come on. weird. So i just wired up a switch and comes on when i want it to, which is the way i wanted things anyways.

For those interested in a lighted switch, I just went to autozone and got their basic lighted switches (Dorman Conduct-Tite blue glow rocker 20 amp interuptor switch) part number 85922. Its very basic but it lights up when activated. I only had to use two of the connectors on the back too. The blue/pink wire got sent to the 12v/on or whatever it said, and I used a quick splice to tap into the cigarette lighter ground for a ground and it works like a charm. Lights up and activates fan when key is forward, vehicle doesnt even have to be on.

Oh and one other thing, I was wondering about this when I first read this. Nobody really mentioned how they ran the wires through the firewall. Maybe everybody else already knows a good way to do this, but I didnt. What I did was make a small hole in the gromet that goes around the hood latch cable. And pushed the wire through there. I know that that is kind of a techty spot, on my mom's jeep. she had some KC lights wired up years ago and then the vehicle always leaked when it rained. Turned out that gromet was gone, fell out or was taken out by installers and water just ran in there. So if you go that route, just make a very small hole so the gromet is intact or use some silicone or something.

Well thats how I did it. Works great for me. Now I just need some hood vents.

There's a rubber grommet near the steering column on the firewall. I go through there.

goalieman24 · 05-08-2010, 03:27 PM

Having a hard time thinking through this for some reason...

But how would this be wired up using a "FitchBox"? With the box under the seat, and switches in the OHC, would there be a way to run the Blue/Pink wire to the box... and still have the switches overhead control it?

Holder350 · 05-08-2010, 07:04 PM

Sure no problem, run a wire thats tapped into the blue/pink wire to your box, wire up the relay with the switch accordingly and instead of using the relay to switch a power circuit off and on, use it to connect a ground to the blue pink wire.

Also, I would rethink putting that box under the seat, water will only run downhill you know.

I have seen more than one of those crappy Honda boxs with the computer under the seats be destroyed by a small amount of water

JBassXJ · 06-03-2010, 03:30 AM

Okay... so... I've followed this thread from conception and left it alone to see if a permanent non-complicated solution would be found for the 97+ guys... I see that this has not happened.

Once a relay gets in the mix or lighted switch, it's just better to not bother with the PCM IMO... I'll repeat, just my opinion. There are some real cool wiring setups though. Us texas dudes would really appreciate something simple that could work here so I'll ask:

I just want to run a wire using that lil' splice connector from the dark blue/pink wire to a toggle switch (just 2 position), and then to ground.

Question #1: Switch: on/on? on/off? Should it truly matter?
Question #2: Is it possible it matters where the switch is grounded? Thus some people getting it to work and others not?
With most electrical modifications, that is the one thing that is not explained, only a few people (one from this thread if I can remember correctly) has explained exactly where he used a ground and that was from tapping into the cig lighter.

Just an average joe livin' in texas tryin' to keep things simple, cost efficient, and the least time consuming so I can go about fixin' other stuff before the sun gets too hot. If anyone has some knowledge or the non-cel guys can let us know where they grounded to and exactly what kind of switch was used, then I think that would truly help out the current mystery.

theducksguts · 06-06-2010, 03:28 PM

I worked on this project last night with another guy on this forum who is some sort of mech/electrical engineer.

On my 2000 XJ we wired the switch from the Blue/Pink wire on the PCM side of things. He said that it was the same where all around and it didn't matter where we spliced into it. He followed the wire all the way through and was sure of it. We grounded the wire and the E fan works great. It is nice having that little switch there for really hot days.

LOIIIIIIIOJ · 06-13-2010, 10:23 AM

Hi,

Im going to try the route of...
Ignoring the PCM and using a separate relay. I'l use a....

Wire straight from batt to a new fuse holder
Wire from a new fuse holder to pin 30 of a new relay
Wire from fan itself to pin 87 of the new relay
Wire from +ve cig lighter to switch with led
Wire from switch with led to pin 86 of the new relay
Wire from -ve cig lighter to pin 85 of the new relay

So when the switch is on...
the cig lighter powers the relay to flick the relay on, which sends power straight from the batt to the fan.

QUESTIONS..

Would this work?
What amps goes through the real fan power wire?
What amp wires do i need for each pin? batt to relay, relay to fan & +ve cig to relay and relay to -ve cig?
What fuse should i use in my fuse holder?
What the best way to splice into the actual fan power wire? - can i use a standard scotch lock?
is using the cig -ve ok as a ground?
Would my switch led light come on?

Thanks in advance