Climatronic fuse blowing

[937carrera]

Brrr, it's cold outside.

It's cold in the car as well as fuse 26, (7.5a) blows, and I could do with some guidance to accelerated diagnosis of the fault.

Replacement fuses blow immediately

What else have I noticed other than Climatronic blank screen ?

Electric mirrors not working
Electric windows not working
Interior light stays on for 30 seconds after drivers door is closed, even when the engine is running

I see from the wiring diagram that fuse 26 also feeds the cooling fan control module

The rubber connectors from A pillars to doors look in good condition, but I have not removed those yet

I have 4 spare fuses, any suggestions what the usual fault is before I start pulling a load of wiring out

[dipstr]

I would check the wiring in the doors first as they are common to breaking

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[937carrera]

Thanks for the reply

I have had chance to have a look at the car again today. The black wire in the drivers doow was broken and the brown earth had wires exposed so I thought everything would be OK after doing the loom repair.

It isn't, and I have done a continuity check from the output side of the fuse to earth and it is showing no resistance so any fuse would simply blow. Pasenger door has a couple of bits where the insulation is cracked but no way should that be allowing a route to earth.

I was hoping to isolate the door component by removing the harness from the A pillar, but although the ring is moving about 8mm in either direction the loom seems to be still fixed at the A pillar end.

I'm going to remove the fan control unbit and coolant fan motor connections and see if the route to earth disappears

[937carrera]

I little firmer anticlockwise force on the door connectors and they are off.

So is the connector to the cooling fan by the battery.

Still a route to earth from the fuse, I tested one of my other GTi's and that shows 233 ohms, so I think it's the centre console out next.

[dipstr]

Oh dear sounds like a lot of stripping to be done. Hope you find the culprit

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[937carrera]

Thanks for the good wishes

The Climatronic is out and disconnected, earth route still exists.

The battery tray is out and I am trying to get access to disconnect the fan control unit. The connector blocks are not wanting to move

[dipstr]

You may need to use a thin flat blade screwdriver as connectors can be a bit of a pig. I know it sounds stupid but try pressing the release lever and pushing the connector further on before then trying to remove.

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[937carrera]

I think I have found the problem.

The coolant fan control unit was putting up too much of a fight, so after some more reading I hooked the battery back up to see if any codes were stored. The usual one for this car was there, 17911 alternator output implausible which I have never got rid of and 16917 G65 high Input PO533. I couldn't get any HVAC codes as the unit was removed and the fuse would blow anyway.

So, I left the coolant fan alone and went on a search for the G65 aircon sensor, the other sensor that is in the circuit. It is accessible from under the right hand front wing, no need to remove the undertray.

I tested the resistance to earth from the fuse output, showing 233 ohms. This looks promising. Removed the connectors to the doors, and it then showed no continuity. My conclusion was that the 233ohm normal route to earth is through the electric windows and the G65 sensor had gone short circuit. I tested the pins on the connector to G65 and none of them was showing a direct connection to earth, so it didn't look like there was a loom issue either.

Reconnected everything, apart from the G65 sensor, and everything is working, no fuses blowing.

A rescan and the engine error codes have cleared, did group 8 the HVAC codes and P01274 had popped up, V71 air flap positioning motor. I cleared that and it has not returned. I'll have to read up on the climatronic diagnosis / reset procedures and do a rescan some oither time

Looks like I need to get a G65 sensor, but I now have heat and a fan, that's good enough for the moment.

[6n2stan]

Hi Carrera,

Was the G65 sensor the culprit in the end? I’ve not been on here for a while but I’m interested in outcomes for future reference!

Cheers.

[937carrera]

Good to hear from you Stan it's been a while. Not much action on this forum, I have been dropping in regularly; either all the cars are sorted or they've all gone off to the great scrapyard in the sky.

Yes it was the sensor.

I tried some continuity tests on the failed vs the s/h replacement sensor to see if a there was something on the readings to confirm a failure. Nothing in particular to note so I ended up fitting the replacement and all was OK again.

Bit of an unusual fault, and fairly difficult to diagnose, but I got there in the end.

... and now you have reminded me I need to look at those other error codes