Hi all,

 

My 08 Estate has had an issue for a while, causing the fans running flat out when the ignition is switched on (whether the engine is started or not). The fans start about 15 seconds after the ignition is turned on and only stop when the key is switched off.

 

I had a condenser leak and no gas for a while, so hoped that getting that replaced and regassed would fixed the fan issue... now done, but no luck... Any ideas what else could be causing this? Some searching here suggests it could be an issue the A/C pressure switch?

 

I also have a fault with the ambient temp sensor (reads negative/very low temps) so have this unplugged at the moment. Fuel gauge is also intermittently faulty... Are these likely to be relayed issues, or another electrical gremlin?

 

Thanks in advance

Still no resolution on this one... Have since had the instrument cluster diagnosed as faulty (explains the temp sensor and fuel guage issues I guess), bit still no idea what is causing the fan to run constantly.

 

If anyone else has experienced this, or has any ideas on where to start on diagnosing the issue, I'd be very grateful.

I looked into this a while ago, and I think your situation is consistent with a broken/dodgy connection between the fan control unit (in/on the main fan) and the engine ECU.  I have a vague memory of this being a green wire.

See here: https://www.briskoda.net/forums/topic/470840-aircon-puzzle-intermittent-cold-output/?do=findComment&comment=5289208

 

 

12 minutes ago, Wino said:

I looked into this a while ago, and I think your situation is consistent with a broken/dodgy connection between the fan control unit (in/on the main fan) and the engine ECU.  I have a vague memory of this being a green wire.

See here: https://www.briskoda.net/forums/topic/470840-aircon-puzzle-intermittent-cold-output/?do=findComment&comment=5289208

 

 

Thanks! Will check the wiring in the morning and see if I can find anything obvious.

Have had the car apart today to check the wiring loom from the fan all the way back to the fusebox and ECU... All the wires and connectors look ok, including the connectors in the back of the ECU itself when we pulled it out. The ECU does have a small amount of white powdery corrosion on the outside bit nothing serious, and the connectors were clean and dry.

 

Checked the continuity of the green control wire (connects to a yellow/purple wire inside the loom) all the way back to the ECU and all fine.

 

The strange thing is that when we out everything back together, the fan isn't running (no idea why, maybe a bad connection somewhere?) but the car now runs really rough and misfires a bit at higher revs/when accelerating. Idle is absolutely fine.

 

Any ideas? Seem to have solved one issue but caused another. My next plan is to change the coolant temp sent... Seems like it might explain some of this behaviour.

 

Otherwise, could it be that the ECU itself is knackered?

A little more information - have just checked with a generic OBD and have error codes P0101 (MAF) and P0299 (boost pressure) showing. Engine light no longer on.

Problem sorted - loose intercooler hose!  🤦‍♂️