Golf IV / Jetta IV :: Fans Staying On All The Time
Nov 20, 2015
I have a 1.6 8v mk4 Golf, and my fans started staying on all the time. There are 2 coolant sensors on this model, one is the green one, and the other is the black one which seems to be hardwired into the thermostat housing. Anyway, I changed the green one, and that didn't solve it, so changed the whole thermostat, which obviously came with a new sensor build on....Hey, it worked, for 2 weeks, and then the fans started coming on again as soon as you turned the ignition key...and the temp needle doesn't move much, as before.
My suspicions have moved to the sensor wiring loom, that was fiddled with, while changing the thermostat...I hear they can become brittle over time, and so behave as if the sensor is unplugged, i guess.... Do these wires unplug anywhere in there so I can test the loom properly?
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A few days ago I was driving around. I get back in my car and when i turn it on no air blows and the radiator fans aren't working at all. My car hasn't overheated but have stopped driving until I can figure the issue out. I have since replaced the fuse box on top of the battery to no avail. I was thinking that it could possibly be the fan control module but in all the posts I am reading not one says that theirs don't work, they just keep running. So is there something else i should be looking at?
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Both my radiator fans run all the time, even if the engine is cold. Soon as I fire it up, even if it's 0 degrees, they are running. To be clear, as expected, the fans do not run if the car is off.
Based on these symptoms, what components could be the culprit?
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So once I start the car the fans kick on, and stay on, even when off. The car currently has no coolant in it and it is not being ran longer than to simply start it. I am guessing the fan control module is no good? Anything else to look for? The car has a new green coolant sensor and the coolant res. is deleted.
Also, what resistor to remove the coolant level sensor? I would like to rid my dash of that annoying light.
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My brake lights are staying on all the time. I changed my brake light switch. This did not work. I took it to the dealer and they could not figure out what was causing this. They felt it could be a wire which might take them 10 hours to trace down @ $95 an hour. I don't understand how a wire could do this.
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As it was such a matter of time, my fans on my 24v gave up during winter, no big deal as it was a pretty cold winter but now that spring is around the corner, I gotta fix this issue. To they change for the same OEM unit that will die in the next 30k miles.
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As the title says, car is overheating. Car gets to 190F within a couple miles drive. Temperature fluctuates between 190F and 225F.
Water pump was replaced ~2 months ago. Was not overheating prior. Temp reached 190F and stayed. Currently has the "black top" coolant temp sensor.
I noticed the coolant fans are not running after I turn the ignition off. This time of year they would usually be running after turning the engine off. If car is overheated and with AC off the fans do not run while engine is running.
I used the guide below to try diagnosing the cause: [URL] ....
Remember both fans should come on in slow speed any time the key is on and the AC is on - if the temperature is above about 32 F (0 C). Both fans run with key on and AC on
S180 (fuse 8, 30 amps, green plastic, above battery) must be good for slow speed operation.
Fuse and holder look good: no melting, no discoloration.
S164 (fuse 3, 40 amps, metal strip, above battery) must be good for fast speed operation.
fuse looks good: unbroken.
To ensure the AC circuits and the Fan Control Module has power check:
Fuse 5 on the cabin fuse panel.
Fuse 16 on the cabin fuse panel. When this fuse is blown the radiator fans will often run unexpectedly.
Fuse 25 on the cabin fuse panel.
All three fuses look good: unbroken
For the first test of the slow speed fans from the radiator thermoswitch have the key off.....Both fans should run in slow speed.
Passed test: both fans run slow
The second test is for the fast speed fans, key on, AC off.... Both fans should run in fast speed.
Passed test: both fans run fast
If the fans run in the tests above, then you should be good to go. No further tests are needed.
If you have been seeing high coolant temperatures and the fans have not been running, then you may need a new thermoswitch.
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So my radiator fans were staying on until my battery died and my car was completely cooled down and off. I was told it was a sticking relay so I replaced it and the fans still won't come on. I unplugged the coolant temp sensor and the fans came on so I know its not the motors or anything.
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Compressor does not engage, and my fans do not come on when I turn on the A/C. They do come on low speed when I jumper pins 1 and 2 on the temp switch plug, but they do not come on high speed when I jumper pins 2 and 3.
I have replaced the FCM with a new one, as well as a guaranteed working used one; neither one changed anything. I assumed right away that it was the fcm because my original one has a hole eaten through it from battery acid.
Compressor clutch ohms out within spec, and it will engage if jumpered.
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I don't understand what is going on I noticed smoke coming from my fans radiator fans and I'm pretty sure that it was motor being fried I've gone to the junkyard and bought a used assembly hooked it up and still nothing could be a possibility that when the motor fried it fried the control module for the fans
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So my friend, ignoring my advice that this generation seems to be riddled with electrical problems, decided to purchase a seemingly nice 99 Jetta, with a junkyard AEG swapped in(AEG is written on the intake and block like a JY would do). Sun roof doesn't slide back, gets jammed, evidence shows water has built up previously and run down the A-Pillar to the fuse box.
I just got the fans unplugged and verified that the fans with power applied, both have their low/high speeds. The fuses on top of the battery are in-tact, no visible melting, looks like the thing is in ok shape(haven't taken them off to inspect the contacts yet).
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So I just got a 2002 1.8t, everything was fine until the fans and ac stopped working. After poking around the forums a bit I changed the following:
1. Fan Control Module. Result: nothing
2. Radiator Cooling Fan Switch Temperature Sensor. Result: nothing.
all fan components have the correct voltage going to them. Fuse 16 for the AC clutch is not blown and has power going to it. The AC compressor has power going to it. The fuses on the battery box have power going to them specifically S180.
My question is what am I missing? is it possible that the fans themselves could be bad? car is not overheating, the after run coolant pump kicks on. But the AC clutch is not spinning nor are the fans. btw AC clutch is not seized up.
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Radiator fans making tons of noise on my newly purchased gli jetta...
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I have a quick question, I got a 2005 mk4 gli, and when the cooling fans go on, only one works, the other one does not, I checked the fuse and its fine.
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I went out to my car this morning and the fans were both running full speed. That's before I even got to it then they carried on doing so when I started the car and still ran after I shut it off. I have stopped them by pulling the 30A battery top fuse for them but what has caused it and how I can fix it? Preferably not too expensively as I am moving house next month typically.
The car is a 2003 1.8t GTI with climatronics ....
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So i have a 2002 1.8t that i got in december. Everything has been great so far untill the other day the car overheated on me in traffic. It was a bit warm out maybe 75-80 degrees. I saw the needle start to climb and then the light went on so i through the heat on full blast and it dropped the needle a bit and turned the light off long enough to pull off the highway. I let it cool down and checked things out. I am not low on fluid, an the fluid was changed within the last year with the vw recommended stuff. The radiator hoses are pressurized so i believe that the pump and thermostat are working. I am thinking it could have something to do with my fans. I tested them in my driveway by supplying them with 12v and the spun perfectly. It only happens when the car is standing still for a period of time. Driving at any speed is fine. Is there some sort of switch that tells the fans to turn on?
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I bought a 2002 gti mk4 with about 127000 miles on it .I did not know the turbo fans were blown out , they were sitting in my down pipe next to my catalytic converter . So I replaced the turbo myself , and 2 hours later the fans fell out of the new turbo , what might be the problem ? why it keeps blowing.
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What could cause both the ASR and ABS lights to stay on? I thought it had something to do with the crank sensor, because a few things i have seen said that was one of the fixes, but I just put a new crank sensor in, but the lights are still on? 03 GTI 1.8t AWP.
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I'm having an issue with my fans on my radiator. They don't turn on when the engine gets warm and the A/C is off. I've replaced the crack pipe, water pump, and belt tensioner. I've replaced the fans not to long ago because the low speed wasn't working. I tested low speed at the fan connector and it wasn't working. After replacing fans I tested and it was working when jumping the pins on the thermo switch connector. I got both low and high speeds to work during that test. I've since replaced the thermo switch to see if it would fix the issue but the fans still won't come on without turning the A/C on. Any other tests I could do or should I just try to get another thermo switch.
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My 03 Golf ac is not working and i am looking for a wiring diagram/ troubleshooting chart. the cooling fans turn on low and I hear the engine surging like the compressor is trying to cycle but it is not.. When I jump the low pressure switch the fans go to high and no power to the compressor. I get a flash of power to the compressor but just a blip every ten seconds. I am trying to check continuity of the ac clutch but having a difficult time getting in there hot. I just bought the car and fixed light body damage on the right front but it was not even bad enough to hurt the washer bottle. Hard to believe the hit caused damage to the ac? AC seems to be charged with about 100 psi static pressure. Why are diagrams so hard to find?
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I have a 2001 jetta 1.8 turbo. when I turn the car off the cooling fans stay on and kill my battery. Ive been told it could either be a relay or temp sending unit but i dont know what one to tackle first, also my coolent temp stays way low almost as if the thermostat is stuck open.
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