Hi everyone, 

 

I've been trying to figure this one out for a few days but think it's time to get some more opinions!

 

The car is a 2004 Skoda Octavia Hatchback Mk II 2.0 ltr TDI with the climatronic system.

 

The blower has always worked (had car since new) and never had any issues with it. A couple of weeks ago I took it in for its MOT, the blower worked on the way in, car passed with no work done, but then whilst driving it away from the MOT I noticed when turning the heating/air con on, nothing happened. Could be a coincidence but who knows.

 

A couple of weeks before the MOT the car had its radiator replaced (old one had a small leak), I think this could be related but more on that later.

 

Anyway I checked the fuses in the interior fuse box (or thought I did) and had some diagnosics done on the car.

 

 

Got the blower motor out and had a look at it, wasn't seized up or anything and span quite freely.

 

After doing a bit of reading I thought the blower motor was the most likely thing to be broken so I got a new on on eBay for £60, but that didn't work either.

 

I then decided to check all the fuses in the interior fuse box again using a multimeter, I found that fuse no. 4 (5A) was indeed blown!

 

 

So I replaced this fuse and turned on the ignition whilst still holding the new blower motor (which was plugged in) in my hand, it span and each speed setting worked.

 

Then I plugged in the old blower motor and did the same and this also span on each speed setting!

 

At that point I thought I'd fixed it and it was just the fuse, so I put the old blower motor back and started the car to make sure it was all working now. The blower motor worked for a couple of minutes but then stopped completely.

 

I checked fuse no. 4 and it had blown again!

 

So I thought perhaps the old motor really is broken and is drawing too much current causing the fuse to blow, but I swapped it back for the new motor and the fuse still blew.

 

So I think that the old blower motor is actually fine and doesn't have any issues.

 

By this point I figured it must be some kind of short circuit to ground on the circuit causing the fuse to blow, so I had a look at a wiring diagram to see what else was on that fuse's circuit.

 

 

 

After seeing the wiring diagram I thought the main suspect was the High pressure sender (G65) for the air conditioning system because of the previous error code on the diagnostics above (0333 High-pressure sensor Open circuit/ground short).

 

This is what made me think the issue could be related to the recent radiator change because I think this could have been accidentally knocked when putting the new radiator in.

 

I had a look at the high pressure sensor and took a couple of pictures of it:

 

 

It looked okay, so I traced the wiring to see where it went.

 

The high pressure sensor wire joined with another (this is the one coming from the left in the picture below) and then went into the thicker wire on the right.

 

 

Now the reason the peg is there is because this wiring was sat on some metal that was quite wet (condensation from the left headlight or something maybe) and it was all I had to hand to try and lift this wire out of the pool of water.

 

Now I'm not sure if you can see but could the area in the red circle be exposing a bare wire to the water and that is what is causing the circuit to short and blow the fuse?

 

Or is it more likely that the high pressure sensor switch is broken and I need a new one?

 

Or could it be something else completely?

 

If I can't go anywhere from here I'll just go see an autoelectrition and see what they say but I'd like to be able to solve it myself really!

 

The fuse does not blow when the ignition is off but it is blowing 2-5 seconds after turning the ignition on (not starting the car), I've gone through a fair few 5 amp fuses so far.

 

Any help at all would be greatly appreciated!

 

Thanks in advance,

Will

5 amps for a heater blower seems to me very light , is it not NO 22 fuse for the blower motor .?   I could be completely wrong though 

 I would change the High pressure switch , cheap and not too hard to change.  

 I would try and insulate the break in the insulation , possibly damaged when changing the radiator . 

7 minutes ago, erindad said:

5 amps for a heater blower seems to me very light , is it not NO 22 fuse for the blower motor .?   I could be completely wrong though 

 I would change the High pressure switch , cheap and not too hard to change.  

 I would try and insulate the break in the insulation , possibly damaged when changing the radiator . 

 

Yes fuse no. 22 is for the Air blower for the climatronic system and has a 40 amp fuse. This fuse is not blown.

 

However, fuse no. 4 (heating, air conditioning, electrically adjustable seats) being blown is what is stopping the blower motor working.

 

As I mentioned above when I first relaced fuse no. 4, both motors worked for a little while before it blew again.

 

Perhaps fuse no. 4 being blown stops the climatronic control unit receiving information form the high pressure sensor and therefore it won't run.

Will have a look at this after eating; there may be even more stuff on the same fuse. Your engine code would help me look.  This is on your car data sticker in the boot, sometimes there's a copy of the same sticker in the service book.

I had a quick look and can't see anything that isn't listed in your info, so favourite culprit is G65 pressure sender, I think.  Try unplugging the loom connector for it, and see if the fuse then holds.

1 hour ago, Wino said:

I had a quick look and can't see anything that isn't listed in your info, so favourite culprit is G65 pressure sender, I think.  Try unplugging the loom connector for it, and see if the fuse then holds.

 

From the wiring diagram below it appears that on the fuse no. 4 circuit there is:

• High pressure sender/sensor
• Heater control unit
• Climatronic control unit

 

So it could be either of the control units too, however from the diagnostics earlier and the fact that the radiator was changed recently I really think it must be the high pressure sensor.

 

Thanks, I'll unplug the connector on it tomorrow and report back!

18 hours ago, Wino said:

I had a quick look and can't see anything that isn't listed in your info, so favourite culprit is G65 pressure sender, I think.  Try unplugging the loom connector for it, and see if the fuse then holds.

 

Okay this might sound like a stupid question but what is the best way to unplug the loom connector for the high pressure switch?

 

I've tried wiggling it and then after watching this video I tried using a flat head screwdriver coming from underneath like the guy in the video.

 

But even when jamming the flat head in from below it just bends the plastic and does not come off. 

 

I'm scared of breaking it after reading here that someone else sheared their switch clean off trying to remove it.

 

Is the best option to just push the flat head in like shown in the video or am I missing something obvious?

 

 

I find this method safest: 

 

 

However you try to release the latch, it always works best if you are pushing the connector further onto the sensor when you try to release it.

If you do this, you'll often hear the latch click open, then you can go to pulling the connector instead.

Edited 13 November, 20196 yr by Wino

33 minutes ago, Wino said:

However you try to release the latch, it always works best if you are pushing the connector further onto the sensor when you try to release it.

If you do this, you'll often hear the latch click open, then you can go to pulling the connector instead.

 

Thanks a lot! Very counterintuitive, I'll give this a try tomorrow.

Yep, it just takes the pressure off the latch so it can move easier.  That pressure is there because there's a rubber seal between the loom connector and the sensor that gets compressed when you mate the connectors. The springiness of the rubber means the latch has a lot of friction to overcome unless you give it this push.  Many a latch has been snapped off through not being aware of this.

I've just unplugged the loom connector to the high pressure sensor (took me 2 seconds now I know how it's done!) and then replaced fuse no. 4.

 

The fuse held when turning on the ignition, so I plugged the old blower motor back in and it still held. I then ran the car for 10 mins or so with the blow motor on varying speeds, everything worked perfectly!

 

At least now I can return the new motor I bought.

 

Here are a couple of pictures of the loom connector and pressure sensor:

 

 

 

There was some green stuff on a couple of the pins, more on one than the other.  Not sure if the the pin with the most green stuff is the live pin or ground one? Does anone know what this green compound is?

 

So does this mean then that the pressure sensor is indeed faulty, or could it actually be the green stuff that was causing the short?

 

Also do you think this was related to the recent radiator change? Does the high pressure sensor need to be disconnected when changing the radiator?

 

I'm glad I decided to investigate this myself, as when I initially took it to a garage they told me the problem was that the blower motor was broken and quoted £200 to replace it.

 

Thanks,

Will

 

 

Will look up the pin functions shortly. Doubt it's anything related to the rad change.  The sensors do have a failure mode where they let water (or refrigerant?) into places it shouldn't get, I seem to remember. Dunno if the sensor needs to be disco'd for rad change, but I doubt it?

I think pin 1 (ground) is on the flattened side of the connector, so the corroded pins seem to be the signal pin in the middle and 12V one on the far side?

It'll be some sort of copper compound, I expect.

 

Clean it all up as much as poss, make sure it's dry, then re-try?  I expect it will cause trouble again, but it might take a while.

 

Google G65 sensor failure and see if there are any enlightening results; I vaguely recall seeing someone had done a cutdown on a manky looking failed one.

16 minutes ago, Wino said:

Clean it all up as much as poss, make sure it's dry, then re-try?  I expect it will cause trouble again, but it might take a while.

 

Will do, thanks. Do you think a wire brush will do the job? Also is it safe to spray some WD40 on to force any moisture out?

 

Yes I've seen that video of the guy dismantling the G65 sensor, very interesting.

 

If it still doesn't work after cleaning the green compound I'll get a new sensor.

 

This is the correct part isn't it - https://www.buycarparts.co.uk/nrf/2389365

Go very gently if you use a wire brush, you don't want to scratch plating materials off the connector pins, just get the green stuff off. I'd be more inclined to use an old toothbrush or cotton buds or something.  WD40 should be OK, don't drown it in the stuff though.

 

Not sure what to recommend with replacement switch, it's been through lots of revisions, but who knows if a new genuine one (part number starts with 5K for the latest version I think) is really much different to aftermarket ones.  There are some on ebay usually at a lot less than RRP. Presumably people buying them and then discovering that the fault is elsewhere in their A/C system.  I vaguely think @J.R. went aftermarket for one, and ended up buying twice? Maybe he'll confirm/deny if available.

Hella or Valeo sensors should be fine they both produce many OEM items.

 

Thats unless it’s actually cheaper from Skoda, worth an ask as sometimes you can be surprised, I was going to pay £15 for a oil pump hex key off eBay but they where only a £5 from VW, then again the rocker gasket for the TFSI was £35 from the dealers or around £15 for an Elring gasket online.

 

The green stuff is corrosion, it can be caused by moisture in the plug, it will induce resistance so best to clean it off, wd40 will help remove it as you guys have already mentioned 

 

 

electrical contact cleaner comes in an aerosol, it will clean your contacts and doesn't leave a residue. Cheap quick solution , poundland type of shop @ £3- £4 a can 

I just cleaned off the green stuff with an old toothbrush and some WD40. It left a little residue but I made sure not to drown it in WD40. 

 

Plugged the loom connector back onto the switch, turned on the ignition and it immediately blew the fuse again.

 

So will buy a new Hella pressure switch as recommended above, £25 - https://www.buycarparts.co.uk/hella/938585

 

Thanks for all the help so far, I will update here when it arrives and I've fitted it.

Just an update on this. After attempting to remove the old high pressure sensor unfortunately I did what someone else has mentioned and accidentally sheared off the entire thing including the one-way valve.

 

It was extremely difficult to access with a 17mm spanner and must have been well and truly stuck on after 15 odd years.

 

 

The above picture shows where it snapped off. Since it is winter now and I won't be needing the air conditioning I've decided to leave it for the time being. Little disappointed but this is the case with old cars. Similar thing happened when trying to change one of the ABS wheel speed sensors, plastic snapped off in the hole.

 

I'm considering changing all 4 glow plugs soon, what are the chances of these being seized and getting stuck/snapping off whilst trying to remove the old ones?

 

Thanks again for all the help.

That’s the only trouble with the aluminium AC pipework, I had to cut the ends off my s4 pipework as I just couldn’t undo the nuts due to corrosion 😫
 

just make sure the engine is nice and hot when attempting the glow plugs, and use the specified undoing torque.

Specified "undoing" torque? - Are you sure?

 

What if they come out easier? What if the wrench clicks and they dont loosen?

 

I think that you mean the tightening torque.

 

Good advice re doing the job hot.

 

I was concerned about removing mine after IIRC 125000 miles and 12 years especially as I have lost my "feel" for when fasteners are going to yield, they all came out OK though (BKC engine)

Nope, Audi have a specified undoing torque for glow plugs or “release torque”

 

if they come out easier, great!

 

if the wrench clicks and they don’t loosen you stop the job, or if they start to go then tighten up you put them

back in again and try another time, or after they’ve soaked in penetrating fluid.

 

its to try and stop you snapping them in the head, first time I came across it was on the ceramic plugs in my A8, but I’m sure I’ve seen specs for metal plugs now too.

 

Here is an A3 BKD engine, but they mention ceramic again.

https://workshop-manuals.com/audi/a3_mk2/power_unit/tdi_injection_and_glow_plug_system_(4-cyl._2.0_ltr._unit_injector_4-valve)/ignition_system_glow_plug_system/glow_plug_system/removing_and_installing_glow_plugs/
 

if I get chance I’ll check on my laptop see if I can find a spec for metal plugs.

 

 

Thanks for the advice! As far as I'm aware the glow plugs have never been changed in the 15 years, so I assume they are still stock. The reason I wanted to change them was because there is a fault code showing for every cylinder:

 

"Glow plug, cylinder 1 Circuit defective"

 

The car still starts fine at the moment but thought it might be a good idea going into Winter. Could this fault code be related to the glow plug wiring instead of the actual glow plugs themselves? I'm a little worried about all the wiring being extremely brittle and breaking something whilst doing the job.