Mk6 golf 1.6tdi issues with rad fan and ac

knipex

Ok I am at a loss.

End of last summer started having issues with AC in my golf. Got pressures checked and the charge is fine (even had it weighed out). Weather got cooler so put it off.

Earlier this year got 2 separate garages to have a look and both told me there are no issues or faults showing on diagnostic.

The pressure switch was mentioned (and its cheap) so replaced that no change.

Search on the net mentions that the radiator \condenser fan must run before AC comes in. Checked mine no fan running. Checked further and discovered that the radiator fan (only 1 in the 1.6tdi) doesn't run at all but coolant temp never goes above 90.

On these there is a fan control module mounted on the cowling just to the left of the fan. 4 wires (2 larger and 2 smaller) to the module and then 2 onto the fan. There is 12V indicated going into the module but no fan. Pulled the cowel out and connected 12 v directly to the fan. it works. Possibly dodgy module.

These are a hardwired unit so ordered a fan and module from a scrappy guaranteed working.

Swapped them out this evening and still no fan running. AC on or off. Ran the car to get it nice and hot and then left it idle for 20 minutes until the bottom pipe to the rad got nice and hot. Still no fan. But indicated temp never went above 90 (and its 22 degrees here.)

With a spare unit now lying around I did some more checking.

I have 12v coming into the module but if I connect this directly to the fan fan wont run.

If I put 12V (spare battery) directly to the module (through 2 larger wires) the fan runs flat out. So I pulled 12 V from the plug directly into the module (just ignore the 2 smaller wires) it wont run. Assuming I have a 12V signal with no current behind it.

Same for both units.

So now I have replace the AC pressure switch, fan control module and fan. but still no rad fan running and no AC.

Is there anything I am missing that could be holding out the rad fan ?

I'm not even going to look at the rest of the AC system until I can get the rad fan running as at this stage I am pretty sure that this is what is holding out the AC.

knipex

Anyone have any ideas ??

The Sidewards Man

The AC fan is a slave to the complete system.

blackbox

Is the blower working OK?

Usually AC won't work unless blower is on and it is getting a pressure signal from the gas pressure switch. Did you check the signal when you replaced the pressure switch?

Fan not working could be a bigger problem. Under normal circumstances its not needed as airflow is sufficient. You might, however, boil if stuck in traffic. If you fake a signal from the temperature switch on the rad it should make the fan start.

knipex

No separate AC fan just one rad fan doing both.

Blower is working fine.

The pressure switch is working fine.

When I plug in diagnostics it tells me no faults, pressure switch OK, nothing holding out AC the compressor is running and drawing power but no cold air.

When you check pressures no change with AC on or off, its not pumping and I cannot see the clutch enabling.. (but diagnostic is telling me its drawing power). When I meter the coil on compressor its metering out fine and when I disconnect the plug I am showing open circuit on the diagnostic.

I am starting to think compressor but don't want to spend that kind of money until I am sure.

iamtony

Have you tried to activate the fan through vcds or similar? These engines don't really need a fan except for when the a/c is running so it probably won't come on all by itself.
Anyway if you can get vcds to run the fan manually you can assume the problem lies in the a/c system you can check to see if the High pressure and low pressure switches are reading within range with vcds aswell.

knipex

Fan can be forced on and is working.

AC system is showing no fault and reporting compressor as running and drawing current. Clutch on compressor is metering out fine (as well as VCDS showing it actually drawing power) but its not compressing refrigerant. Plus I cannot actually see clutch engaging.

iamtony

knipex wrote: »

Fan can be forced on and is working.

AC system is showing no fault and reporting compressor as running and drawing current. Clutch on compressor is metering out fine (as well as VCDS showing it actually drawing power) but its not compressing refrigerant. Plus I cannot actually see clutch engaging.

Sounds to me like the compressor, or the clutch is gone, can you feel/hear it kicking in at all?
Not much too see regarding seeing the clutch engaging they are usually electromagnetic so not much movement to see.

knipex

iamtony wrote: »

Sounds to me like the compressor, or the clutch is gone, can you feel/hear it kicking in at all?
Not much too see regarding seeing the clutch engaging they are usually electromagnetic so not much movement to see.

My suspicion also but whats putting me off is the fact that the clutch is drawing power and metering fine which would lead me to believe it is working and the compressor isn't noisy or rattly or overly hot..

Compressor isn't that cheap that I can buy one, fit it, get the system vacced and charged just to test if it works so I need to be 100% (Or at least 99.5%) sure that it is the problem.

iamtony

Yeah it's a weird one. As much as I hate to say it it might be time to give it to a professional it might work out cheaper.
If the car isn't turning on the fan with the a/c then it knows it's not working if you get what I mean.

martinr5232

Is your air con getting cold at all ?? How many wires go to the fan module ??

knipex

Nothing from AC the compressor isnt pumping at all.

There are 4 wires to the fan control module (2 about 2.5sq and 2 about .75sq) and then 2 wires to the fan.

Put 12V into the module (through 2 larger wires) and fan runs flat out. Put in 8v and it runs about half speed..

Have brought it to two garages 1 vw main dealer who said gas, second one was a good indy does alot of VW's and he in his own words is at a loss. He says best guess is compressor but that is a guess.

martinr5232

Im not that familiar with vws but id imagine you have a main live and earth and two switching wires from the engine ecu so either your ecu is not sending a signal or its a wiring problem to or from the ecu.

knipex

martinr5232 wrote: »

Im not that familiar with vws but id imagine you have a main live and earth and two switching wires from the engine ecu so either your ecu is not sending a signal or its a wiring problem to or from the ecu.

If I plug in the diagnostics and force the fan on it runs which would indicate all outputs, wiring, fuses, relays etc are OK. Temperature is reading correctly, everything is fine. If it were not for the AC I would just out down the rad fan to the engine not getting hot enough to need it. Those 1.6tdi engines apparently put out little heat and can run with no fan.

With the AC the diagnostics tell me its working fine, noting holding out, power going to the compressor and its actually drawing power. Everything l;looks wonderful but the compressor isn't actually running.

George Dalton

Compressors are very troublesome on these so that is more than likely your issue as well.