Cooling Fan Not Working, No Dtc's

[pdaly]

I've got a 2007 MKIII Galaxy Ghia and the air con will not work which looks as though it's caused by the cooling fan.

 

With the air con on, the vents are pumping out warm air. It's cooler with ac off.

 

I understand that the PCM won't switch on the air con compressor unless the radiator cooling fan is running.

 

To test the cooling fan, using the on board diagnostics, I've watched the engine temp increase to 108'c whilst fast idling the engine. I read that 104'c and the fan should kick in. The fan refused to start.

 

I tested the fan by unplugging above the fan controller and feeding 12v across it and the fan ran no problem at all.

 

I plugged in a OBD2 reader and it reported no DTC's

 

It's pointless testing the compressor unless I can get the cooling fan to work. Maybe the fan is stiff? And normal running voltage is not strong enough to start it??

 

Any advice please?

[steveeeee]

I have the exact same problem!  From what I've read, the most likely culprits are either a break in the purple wire leading from the fan controller (see here and here) or a faulty G65 pressure sensor (not 100% sure yet if the mk3 has one) (see here and here).  I also get no error codes on my ODB2 reader using Forscan, but apparently this is quite common as a number of air con related faults don't throw errors.  Next time I have a block of time (difficult with 3 kids!) I want to try and find the other end of the purple wire so I can do a continuity test with a multimeter.

Edited May 15, 2017 by steveeeee

[xavier]

I take it you've had the air con pressure checked and that's ok?

[stevejannicole]

Got the same prob. The purple wire is broken right at the base of the module plug. Any idea where I could get another plug or even a loom with the plug, as I could splice the wires,because I noticed they're bonded in.

[BrianH]

Either a scrapyard and find one suitable, or find one being broken up on ebay or similar and ask if its available?

[steveeeee]

I take it you've had the air con pressure checked and that's ok?

 

I had the system re-gassed (special offer £20, so worth a try as a troubleshooting step). They said it wasn't completely full before they started but it wasn't terribly low either.

 

The purple wire seems to disappear under the engine bay fuse box and I can't tell where it comes out.  Does anybody here know where it goes to?  I'd really like to check continuity first before I start chopping things up.

[pdaly]

SOLVED (the hard way):

Garage didn't have time to diagnose Air Con as we were going away on hols. But they did a full recovery/refill of fresh air con refrigerant. However we broke down the following day as we were leaving to go on hols. Car overheated. caught it in time, and attached cooling fan directly to car battery... RAC and Garage said to carry on with it wired like that until we source the fault.

 

The ODBII reader was a waste of money... bought another (ELM327), and it gave me the dreaded  P0691 error.... So it was either a faulty PCM, violet wire or Fan ECM. 

I finally traced it to the violet wire from the Fan module to the PCM. Rather than open up the wiring loom, I've hardwired a new cable to replace the purple wire.

 

All sorted now. Fan working fine and air con nice and cold... shame the heat wave has gone and its now started raining!!!! 

[pdaly]

 

I take it you've had the air con pressure checked and that's ok?

 

I had the system re-gassed (special offer £20, so worth a try as a troubleshooting step). They said it wasn't completely full before they started but it wasn't terribly low either.

 

The purple wire seems to disappear under the engine bay fuse box and I can't tell where it comes out.  Does anybody here know where it goes to?  I'd really like to check continuity first before I start chopping things up.

 

 

Steveeeee,

 

it took me ages to research to make sure I knew what I was doing, but it worked, this is what you need to know...

1. Remove Left wheel arch and mudflap (a few screws and plastic clips). No need to remove wheel, but it would give you more space.
2. Behind the bumper, in the wing (under headlight), you'll see a white plastic box. Unclip that white cover (clips off at bottom of box)
3. you'll see a metal security guard, there's 1 tamperproof bolt. you can inscrew it 1 of 3 ways:
   1. drill hole with 3.5mm drill, then use no.20 torx driver to unscrew. (didn;t work for me)
   2. hacksaw a slot across bolt and use flat screwdriver (didn;t work for me)
   3. using hammer and flat screwdriver, tap across the bottom edge of bolt to start unwinding the bolt (that worked)
4. Once unscrewed, you can remove the metal guard (slides towards you a little)
5. There are 3 wiring loom connectors, grey (nearest,) brown (middle) and blue (furthest/towards front of car)
6. There are 2 violet wires (1 in grey and 1 in blue) the one in the blue connector read 3.8volts (i think its supposed to be 4.4) and then 12v when engine/aircon switched on. It is this cable that you need. The other cable was reading tiny voltage (0.1v) and I think that is for the power steering angle sensor.

I tested both ends for continuity and there was definitely a break in the cable. so rather than tracing the break in an old cable, I sliced into both ends with a new cable to create continuity and once I reset the DTC, the fan worked. So I cut the cable and permanently replaced the cable with a new one and it has now been working perfectly all week.

Edited June 7, 2017 by pdaly