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Please help me with this aux fan switch before I light my POS Jeep on fire. Pics!

90Pioneer

NAXJA Forum User
Location
USA
OK, this is starting to REALLY piss me off. All I want to do is wire in a simple aux fan switch. But nooo, it can't be easy...

Here it is from the begining....

I have a 1990 Jeep Cherokee Pioneer w/ the AW4 tranny and 231 TC. It's getting a bit warmer around here and the XJ started to overheat a bit while idling in traffic, since the aux fan wasn't kicking on.

So, I found Craig's write up, http://www.olypen.com/craigh/auxfan.htm .

I went out and bought a two position lighted rocker switch from Shucks. Following Craig's directions I ran, I spliced into this orange wire, shown here:

orangewire.jpg


Picture does not show the splice, just references the wire. I than ran the new wire through the firewall to my rocker switch.

Once this was completed, I plugged a wire into a slot in my fuse box (hot when ignition on) and ran it to my rocker switch, as seen here:

fusebox.jpg


Picture does not show the wire I plugged in, just a reference of my fuse box. I just want everybody to be on the same page as I am. I

Once this was done, I wired in a ground for my lighted rocker switch, and installed it in my console, as seen here:

switch.jpg


Once everything was wired up, the switch seemed to work great. I don't remember exactly, but I was messing around with my AC settings, and may have turned on the AC while I had my aux fan switch running. Anyway, I do remember both my fan and AC working just as normal.

The next morning, I start my XJ up (aux fan switched off), and turn on the AC. It comes on for a few seconds, I hear a "crack", and it stops blowing. Sure enough, 25amp blower fuse is blown. I replaced the fuse, turned the AC back on, and the fuse blows again.

I test my fan switch to see if the aux fan will come on, and it works fine as it did the day before. I decided to do a bit of experimenting, and I unplugged the power from my fux box which went to my new rocker switch. The blower still blew the fuse. After a little head scratching, I unplugged my AC clutch fan control switch (do not know if this is the proper term or not), and presto, the blower stopped blowing fuses but would no longer blow cold air.

A couple hours later I had the crazy idea of removing the splice on the orange wire. I plugged the AC clutch fan control switch back in, and sure enough, it didn't blow a fuse. But at this point I was right back where I started.

So I jumped on the forums, and NAXJA told me I didn't even need a power for my rocker switch, and to just wire it to the black wire and the white wire on the fan, as you can see here:

blackwhite.jpg


So, I sliced into these two wires below the connector plug for them. Now one of them was black, and the other was red with a white stripe.

Here is a picture of them spliced in with the wires to my rocker switch:

overview.jpg


Connections look a bit rough, but trust me they were good and solid. After I was finished I fired up the old XJ, and turned on my rocker switch. It didn't light up as it had done the first time, and the fan didn't come on either. Honestly I wasn't really suprised. I turned my AC on to see if it would blew a fuse, as it had done on my first attempt.

Well, it didn't blow a fuse, but I quickly smelt the awful smell of melting rubber, or similar burning stench. I quickly shut my car off. Since the fan switch didn't work, I sniped the new wires a couple inches before the splice. So it was basically as it was before I started.

I started the XJ back up, and turned the AC on. I didn't get the burning smell this time, but my aux fan wasn't turning on, as it usually does with AC or defrost. The engine was pretty cold, so I drove around a bit with the AC on max, hoping my aux fan would kick on after the engine warmed a bit. I kept hearing the familar "click" or "pop" before it turns on, but it just never came on, dispite the clicking.

So basically, I am right back where I started, except I now possibly have a fried aux fan and or aux fan wiring. Is it possible my switch could now also be toast?

Someone please help me figure out what I am doing wrong and why I can't get something this simple to work. It's REALLY starting to piss me off.

Sorry for the long post, but I need help!!

Thanks
 
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Hmm...this is just an armchair (well, deskchair) thought process here, and my fan wiring isn't stock..but here is how it's wired stock as I remember, and how I plan to wire it when I change it.

fan.gif
 
I unhooked my factory fan altogether and ran it off of a switch. The computer wasn't smart enough to turn it on when needed so I ran it through a manual switch. Try disconecting it from the ECM altogether.
 
Not quite sure how to PM you SeanR, but my email is [email protected]

GSequoia, that is exactly how I had it set up on my first try, using Craig's write up. The only difference is I spliced into 85 (which you have listed as ground, and it worked but blew fuses when AC was on, as described before). I chose this wire because that is the one Craig said to splice into, the orange wire. Should I try splicing into 87?

I am at a loss. I think I will go try unplugging the fan and just running a straight 12 volts to it...
 
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SearR, I got your PM but I am too dumb to figure out how to reply to it, other than using the forward button?

Anyway, I tried flipping the switch, and it wouldn't move. WTF I thought so out came the switch, and the back of it was melted like butter on a frying pan.

This go around, I decided to bypass all of the factory wiring for the fan, and took 12 volts off of the fuse box again. With the switch hooked up directly to the fan it now works great. No fuses are blowing, aux fan works fine, as well as AC. I'm pretty happy.

I inspected the relay it had and flipped it over. There was so much corrosion in it I can't believe how it was even making a connection in the first place.

Thanks for the help everybody!
 
The corrosion may have been the problem. I tried to unplug the aux fan relay on my '88 MJ and two of the terminals broke off and stayed in the relay socket. There wasn't enough left to grab with needle nose pliers, so I ended up having to cut off the relay socket and use female spade terminals directly on the wires and plug them into the relay individually.
 
GSequoia said:
Hmm...this is just an armchair (well, deskchair) thought process here, and my fan wiring isn't stock..but here is how it's wired stock as I remember, and how I plan to wire it when I change it.

fan.gif


There is another way to do this, but this is better, cause you only need to run one wire into the cab, but here it is anyway.

There is a temperature sensor in the radiator that has two wires going to it. It is just a big hex head threaded into the radiator on the drivers side. When the water in the radiator gets hot enough, this "sensor" shorts or closes and then the fan kicks on. Just wire the switch across "in parallel" with this sensor and you are done. The electrical system thinks the sensor went closed because of hot water, but really YOU wanted the fan to come on. To check this out before running all the wire, unplugg the sensor and short the two wires together that go back to the engine and watch the fan turn on. Now you can wire up that switch with confidence!!!!!!!!!

james
www.geocities.com/jammerjamesharmon
 
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jammerjamesharmon said:
There is another way to do this, but this is better, cause you only need to run one wire into the cab, but here it is anyway.

There is a temperature sensor in the radiator that has two wires going to it. It is just a big hex head threaded into the radiator on the drivers side. When the water in the radiator gets hot enough, this "sensor" shorts or closes and then the fan kicks on. Just wire the switch across "in parallel" with this sensor and you are done. The electrical system thinks the sensor went closed because of hot water, but really YOU wanted the fan to come on. To check this out before running all the wire, unplugg the sensor and short the two wires together that go back to the engine and watch the fan turn on. Now you can wire up that switch with confidence!!!!!!!!!

james
www.geocities.com/jammerjamesharmon

Exactly the way I did it. Very simple, no extra relays or anything to mess with and all the switch is doing is providing a ground to the circuit.
 
Okay, I really apologize for going off topic, but I gotta ask if you really need the switch at all?

My 89 was "hotwired" when I bought it, when the key is "on" the fan is running, and I've seen no problems.

The 90 I just bought my g/f didn't have the aux fan wired at ALL. Yes, it overheated. A lot and badly. So I just wired it like mine, swapped the 7.5A fuse up to a 15A, and so far so good...

Is this bad? And if so, why?

Thanks,
Robert
 
All you guys wiring in these fan bypasses and fan relays and what not are missing the problem. WHY is it running hot. Solve that problem and you don't need all these jury rigs. They are not running right either because of the rad, fan/fan clutch, thermostat or pressure problem or the engine needs a really good 7 hour enema flush and a refil or a combination of them. I take care of my system and flush the old coolant EVERY year, it amazes me the amount of crap that comes out when I do it. Like, hows all that stuff get in a sealed system. My 98 stays rock solid at 210, my aux fan ONLY comes on with the compressor and the reason for that is so the fan can move more air thru the rad and that ac rad in front, the fan is suppose to come on when the compressor is pumping hot freon thru to condense it back to a liquid to begin the cycle again. I admit the switch is a good thing but to put one in and call the problem fixed is wrong wrong wrong, all you did was a workaround...
 
I agree with richp... I am still putting in a switch b/c it comes on way to hot, and plus i have control of itso i can turn it on when i am wheeling, but other than that i dont need it, flush your system the reverse flush works wonders, and makes it cool so much better, I also add water wetter tho too.

nate
 
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