Golf IV / Jetta IV :: AC Will Not Activate Until Engine Gets Hot Enough That Radiator Fans Turn On
Jun 3, 2016
I have an odd problem. My AC will not activate until the engine gets hot enough that the radiator fans turn on. Once they do, the engine RPMs drop, the clutch kicks in, and I get frosty cold air with no problems. I already replaced my FCM and checked all fuses. It worked consistently all last summer and considering the AC is nice and cold once it kicks in, I don't think this is a pressure issue and it was recharged at the beginning of last summer by a good shop.
I changed my coolant flange a few months ago, same temp sensor. Didn't try AC back then as it was cool outside still. Could this have something to do with it? I have proper readout on my dash. Maybe it's the ambient temp sensor?
2.0 Getta GL AEG 230,000 miles.
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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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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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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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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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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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So this seems to be a common code that is thrown when you near 100k miles, I'm at 77k .. This thread seems to be the most organized [URL] ....
"Long story short, there are 5 main reasons this problem can pop up, listed in order of likelihood, least to greatest:
1) Coolant sensor
2) Thermostat
3) Bad fans
4) Coolant mixture
5) Water pump "
My issue is that the only ones I'm (probably) able to rule out is coolant mixture and bad fans. My radiator fans do turn on from time to time, so I thought I'd ruled that out (unless it would throw a code for not turning on at appropriate times?)
I heard of a test to turn on your AC and see if they turn on, but my AC hasn't blown cold air like ever, so I don't know if that affects the test (probably not?)
A couple years ago I had a shop replace the original thermostat with the new one, or was it the coolant sensor, or both (ugh, I don't remember!) That leaves thermostat, coolant sensor, and water pump.
I guess my main question is is there anyway to find out which it is between these 3, without spending so time, money, parts etc? It doesn't seem the coolant sensor is easily accessible for one.
My car has been really slow recently but I also need to change the spark plugs, I'm doing that this week. I cleared the CEL/P2181 code and it returned a few weeks later,
I'm starting to change my mind about this car being easy to maintain/reliable, I'm always on time with maintenance and with only 77k miles on a 2004 car.
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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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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 m having trouble figuring out why the radiator fans wont turn on, Even when the ac is turned on it still doesn't turn on, I changed the coolant temp senser. still nothing, i also ran a whire from the battery to the fan and they both turned on. I also stitched around relays and checked fused still nothing. 2000 pontiac grand am 2.4L engine 4dr auto trans.
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The fans in the engine bay wont turn off. As long as the car is on they run. they do turn off when the car is off.
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I bought my 2001 Jetty w/2.0 only yesterday. While I was looking under the hood this morning, I noticed there was no fans running while engine was going so I took a trip to local auto parts store. O'Reilly's hooked up my Jetty and told me there was four error codes but they weren't sure what they meant. Here are the codes: P0302, P0301, P1128,and P1580. I have no clue of what these errors mean. I am not familiar with Volkswagen at all and there are no volkswagen dealerships close.
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So I noticed my temp gauge was starting to rise when I was on the freeway. I figured my fans were out but I just opened my hood and both fans were spinning. When I turned the car off both fans turned off but the temp gauge was almost into the red.
In the morning I turned on my AC and only the passenger side fan was working.
So I am not really sure what my next diagnostic step should be. The engine was not radiating any heat so I am not sure that it is even actually running that hot. Could it possibly be the temperature gauge? If I got a vagcom would I be able to check the actual temperature from there?
I am also concerned on how to find out if the fans are running at both speeds at the appropriate times.
Not sure if this is related but my cruise control stopped working a few weeks ago also.
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1993 Honda Accord LX (263,000 miles). My headlight indicator alarm does not activate when I turn off the engine with my headlights on. I have looked at all fuses. Problematic in the morning after sun rises and can no longer see the headlights .... dead battery.
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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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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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Started the R and moved it out of the garage after the motor build. At which during that time I replaced the large fan with a new one from Ecs and the small one I took apart and cleaned up after I found the Diy for it.
Before I rebuilt the motor the car started to over heat on its last ride home before the rebuild (Neither one of the fans would turn on). So I replaced the switch on the radiator today and let the car warm up and the fans didn't kick on again. I checked the fuse and it good but I'm not sure where the relay is.
Also my A/c is not charged up. I also touched the coolant lines running to the Aux radiator and they are cold. And I do hear the after run/electric water pump running.
The green coolant temp sensor is clean and plugged in. Could it be the thermostat? Are there any fuses in the panel that sits on top of the battery that deal with the fans? Is there a way to test the coolant fan control module?
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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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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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