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Dan - the guru of Fans at the TDI club authored the following post that is the go to for fan operations, diagnosis and repair.

Check your radiator/condenser fan operation NOW - TDIClub Forums

I have been working with him on my own issue and mentioned to him that I would be re-posting his info and how-to's here and he said that all New Beetles would benefit from the advice he had.
 

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VW Junky
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Ive replaced both of my cooling fans and flushed the system :D,my baby is ready for the heat!!:cool:


For the first time since ive owned the bug,my cooling fans remained on after i turned off the ignition,i was worried at first,then i realized it was that time of year.
 

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OK I have been doing some reading so I can talk "A/C" to my NB's and it is a complicated language; not to mention the various dialects for certain model years. The reason I have done this is the wife's A/C has started shutting itself off, translated, melting the battery fuse block casing around the 30 amp fuse, and this occurs in stop and go, city traffic where the speed is 40 mph or less. I put a 15 amp fuse in it which blows without melting the plastic; a 20 amp fuse will still melt plastic. I used a rat tail file to reshape (fix) the fuse block.

One thing odd I did notice was that as long as the car is doing 40 mph or faster without any stops the A/C system works as advertised, even with a 15 amp fuse. So what A/C component is upping the power to which component?

Here is a list of the Sensors, Switches and Valves for the A/C system.

1) A/C Refrigerant High Pressure Switch F23 - Switches the coolant fan to next higher speed upon an increase of the refrigerant pressure to 16 bar.

2) A/C Refrigerant High Pressure Switch F118 - Switches off the A/C compressor when the refrigerant pressure reaches 32 bar.

3) A/C Refrigerant Low Pressure Switch F73 - Switches off the A/C compressor when refrigerant pressure drops to 2 bar.

4) A/C Pressure Switch F129 (Valve) - Does three things...
A) Switches the coolant fan to next higher speed upon refrigerant pressure to 16 bar.
B) Switches off A/C system if refrigerant pressure reaches 32 bar.
C) Switches off A/C system if refrigerant pressure drops to 2 bar.

5) A/C High Pressure Sensor G65 - Sends refrigerant data to the following Contol Modules and which control the cooling fans, A/C Clutch and/or A/C Compressor regulator Valve N280
A) Fan Control Module
B) Engine Control Module
c) Climatronic Control Module or A/C Control Head E87

6) A/C Pressure Temperature Sensor G395 - sends refrigerant data to the Climatronic Control Module J255, which in turn controls the coolant fans and the A/C Compressor Regulator Valve

7) A/C Refrigerant Shut Off Valve N43 - Switches refrigerant flow through the evaporator on or off.

8) A/C Compressor Regulator Valve N280 (internal component of the compressor) - Regulates the low pressure side of the refrigerant. If this valve is your problem you will need a new compressor.

Now depending on your the model year (dialect) of your NB, you will have one of the following A/C sensor system component setups...

1) F23, F73 and F118
2) F129 replaces F23, F73 and F118
3) G65 Replaces F129
4) G395 replaces G65 or F129

I have not read enough to determine which A/C system component setups comprise which model years. As soon as I determine this info I'll update this post.
 

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I see there is a PDF file for the function/locations of the J293_FCM does anyone have the same file for the 1J0919506H FCM (10 pin model)

Thanks
 

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help

ok...I have been reading through some of this, but it is all very technical and over my head...I have a 99 new beetle and the a/c is itermittently blowing cold...it seems like when the weather is really hot the clutch on the compressor pulley will not engage and it blows hot air....when it is a little cooler the clutch engages, the compressor kicks on and it blows cold air....anyone know what the problem is and what needs to be done to fix this?? from what i read here it looks like it is some kind of sensor. IS that correct? and if so where is it located?
 

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If you need to change your fans, check the wiring, one fan has 3 wires and the other one has 3 or 4 wires. They are not interchangeable.

BTDT
Neil:mad:
 

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A/C still will not work!!(Clueless)

Dan - the guru of Fans at the TDI club authored the following post that is the go to for fan operations, diagnosis and repair.

Check your radiator/condenser fan operation NOW - TDIClub Forums

I have been working with him on my own issue and mentioned to him that I would be re-posting his info and how-to's here and he said that all New Beetles would benefit from the advice he had.
I look at the links that you posted and went to check my a/c compressor and this is what I found.
The compressor is not getting voltage. I took out the fan controller and tested the wiring off of the a/c switch and the blue wire with red stripe is getting 12 volts when the switch is activated which tells me that the a/c switch is working. I have replaced the fuse block on top of the battery with a new one and that did not fix it. I replace the FCM with a new one and that did not fix the problem. I then pulled up the relay location that you posted and on the relay block on my 2000 VW Beetle with a 1.8 turbo has empty spots in the relay block in spaces 11,12,and 13. I also checked the FCM on wire or pin 14 on the 14 pin plug and am getting no power. I do believe that in your post that the wire 14 is what supplies 12volts to the FCM. I am lost! Please help before I go insane!! Oh I also checked the power to the compressor and no power when testing the wire for voltage, but you can test the with a test light hooked to 12 volts and the light lights up like both wires going to the compressor is grounded?? I am very confused.
 

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beetle 1998 electrical diagram ?why so obosete?

EEEEEEExcellEEENT !!!!! info !!!!!
going alot deeper than i wanted ,,but GreaT!! info !!!
Learning curve about vw a/c is good!!
Q: why is regualar electrical diag so hard to come by.
I am used to basic diag that shows wire to wire to sensor to wire to wire to sensor to wire to relay to wire to controler to wire LOLOLOOL!!!
 

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This reminds me..

This year it hasn't been that warm yet, but when it has gotten warm, I use the A/C and the fans run.

At any rate, I don't ever recall hearing the fans kick on all by their lonesome yet this year. (I don't normally drive a lot anyway).

I know the temp thingy works. It shows blue or cold in the morning before I make the quick trip (2 miles maybe) to the bank. Anytime its driven more, its on the highway and the fans wouldn't have to run anyway. Guess I should check that out. >.<
 

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This reminds me..

This year it hasn't been that warm yet, but when it has gotten warm, I use the A/C and the fans run.

At any rate, I don't ever recall hearing the fans kick on all by their lonesome yet this year. (I don't normally drive a lot anyway).

I know the temp thingy works. It shows blue or cold in the morning before I make the quick trip (2 miles maybe) to the bank. Anytime its driven more, its on the highway and the fans wouldn't have to run anyway. Guess I should check that out. >.<
I'm having the same problem with my 2.0. If I switch on the AC, both fans spin. If the AC is off, the fans never seem to run even when the air temp is 90-100*F. So I'll be reading through these docs and the Bentley and doing some testing.
 

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Cooling fans...

My cooling fans don't come on when I turn on the a/c or when the engine gets really hot. I know they work, I tested them. I thought it was the thermo switch, so I changed it. Still they don't come on. I'll be conducting further tests soon. Anyone have any clues to what the problem might be?
 

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I could relate to this problem. Ok, first I had taken my '03 Turbo S to get my water pump replaced and while they were fixing it they said that my fuel pump relay was bad so they wired in a Ford relay for the meantime. My ac doesnt work now, before the fix it did and now it doesnt. Since I'm relatively new to the VW scene (previous Suby owner) I need some help as to troubleshoot the problem. Does the fuel relay have a direct relation to the AC not working and/or working? If someone has a schmatic or diagram as to properly wire the relay back I can do that since I have the proper relay in hand. If it has no relation to it, could it be a sensor?

Help the noob.
Thanks!
 

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First off I would like to say thanks to all that have posted this info. I am working on a 2002 NB 1.8 turbo. All fuses tested good. For the life of me I can't get the plug on the thermo switch unplugged at the bottom of the radiator just above the lower hose. So I can't test it I have read lots of the info on this site and it is very useful. I don't have a Bentley. I would like to add something to the testing, by mistake I thought the coolant switch at the Y in the upper hose was the thermo switch. But it only has two wires if I unplug it and jumper the connector I get both fans at high speed and the compressor kicks in with the engine running. What is this switch called. I have not seen this posted anywhere. This is a car that belongs to a car lot and they have another NB well actually a couple of them. So we swapped out the fan control module from the one I am working on that would make a sound at the passengers cooling fan when you turned off the key. So that means a dead battery. If I remove the S180 30 AMP cooling fan fuse the draw goes away. The other NB works fine with either Fan Control Module on it.
Ok let's back up here for a second or two. When this NB was brought to my shop it died on the way here. Luckily they had a jump box and battery jumper cables and were able to get the car here. I found that at the S177 Alternator wire on the engine side was getting super hot like close to 300 degrees. I took it apart cleaned it and it seemed to be a lot cooler. But that was a week ago this morning the problem has reappeared. So I am wondering if this resistance is causing me grief. And wish someone could explain how to get the lock off the thermo switch connector. These bi focal glasses make it hard to see the lock and it is turn towards the fan.
 

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OK I am scratching my head now. The fans started working and so did the A/C.
I found this after I posted the previous post.
1. The auxiliary water pump can run for up to 18 minutes after the car is turned off depending on the coolant temperature. Should the pump run longer, then diagnosis of the fan control module and pump circuits will be needed.

2. Should the pump shut off within the specified time and the battery will still not start the engine, then perform a battery load test and charging system analysis.

I would first replace the temp sensor, if for some unseen reason it does not work right after the sensor change, put a new Fan Control Module (FCM) J293 in it. Even if it just needed a FCM, it was a good idea to change the sensor anyway.
After reading this I got the stethoscope back out and sure and behold it is the auxiliary water pump that is running, it is fastened to the passengers side fan and the noise can be heard in the fan but is actually coming from the auxiliary water pump. The pump did shut off within the specified time.
 

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Wow

Been reading this thread and it sounds like i have alot of testing to do, or just start replacing sensors and fcm. lol will be refering to this thread alot .:rolleyes:
 

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I'm having the same problem with my 2.0. If I switch on the AC, both fans spin. If the AC is off, the fans never seem to run even when the air temp is 90-100*F. So I'll be reading through these docs and the Bentley and doing some testing.
I got confused after the first two tests (fan lo/hi), which the car passed.
Is there a way to test the thermo switch (3 contact) - or do I just replace it?
 

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After you've eliminated everything except the thermoswitch, hook up an OBD reader to monitor coolant temperature and let the engine idle. The fans should come on at low speed before it reaches 210°.
 

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So I replaced the thermo switch at the bottom of the rad and flushed & filled with the correct coolant today. I'm still chasing a big bubble (no heat).
Still, the fans only come on at the appropriate speed when the A/C is on. Without the A/C, the engine would probably catch fire before those fans come on. Not good.
Being summer, the car can be driven as long as the A/C is on, but that's not the fix.
There are two more cooling system sensors I found - a 4-wire one just about below the air filter pipe (that goes to the turbo_ and a 2-wire one at the front of the engine; is the front one the A/C cutoff? What about the more-rearward one?
I'm stumped :-\
 
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