My Mk1 Octavia L&K TDI 2003 had a completely flat battery last week after displaying no starting issues the previous day. This occurred again the next day after a full battery recharge.  I started to diagnose the problem by checking the alternator output  which was fine at 14+ volts. I then clipped an ammeter between the battery +ve terminal and the terminal connector and measured a variable quiescent current between 0.5 and 1.5A. The next step was to pull the fuses one at a time and note the current.  This was tedious as it required the drivers door to be opened each time to access the panel which triggered the interior light and door light delay so I pulled fuse F14 and unclipped the red courtesy light in the base of the drivers door to get a steady current reading for each test. The gave a steady continuous current drain around 0.5A with the car static. To cut a long story short, it was only when I pulled 10A, Fuse 16 (Haynes reference manual)  that the current drain dropped back to around the 8mA expected leakage through the alternator diodes. F16 was labelled Air Con , Electric Water Pump. I suspected a stuck relay but Haynes contained no relay info. 

 

However, having found a culprit, I hit a brick wall.  I can find no online info on any relay that might be behind this fuse, its part number/type or its location or where this electric water pump is located. The only posting in the forum that came close was made in 2013 by UglyBug, "Relay For Aux Coolant Pump" but that was for a Mk2 Octavia. Member comments in that posting talked of a CCC (Continuous Coolant Circulation) relay located in an eBox next to the main high current fuses near the battery itself. My car has no eBox that contains relays, only a shallow box containing 4 high current strip fuses + 3 normal fuses.  

 

Can any member please tell me where this relay is located, what type it is or where the electric water pump might be on my ASZ engine type in a Mk1 car?  The relevant wiring diagrams for the Climatronic Unit would also be a bonus

 

Thanks in advance!

 

Fuse # 16 supplies the AC control panel (pin 7 of 16 pin black connector) and the radiator fan control module (pin 4 of the 14 pin connector)  

Thanks for the info! A VW forum indicated that these control modules are normally mounted low down on the LHS of radiator fan matrix which gave me a starting point.  A search on eBay gave me an image of the module part # 1J0919506 with a variable single letter postfix that would seem to vary according to whether it was for full Climatronic or simple AC.

 

 For the benefit of others, my inspection revealed the module was mounted face down on the RHS beneath the battery support shelf on my car.  Until I can remove the battery, release the two holding bolts & twist the unit over I cannot see the relevant part number in full which is a job for tomorrow!  I am hoping that if I release the 14 pin connector, with Fuse #16 in place, the current drain will drop to 8mA  which would indicate the fault to be in the module itself & not the panel which is not displaying anything with the ignition off.  Here's hoping!

 

Thanks again as I would like to keep the car going as it has only done 66000 miles in nearly 20 years of faithful use with the original refrigerant in the Air Con!

7 minutes ago, iochroma said:

 I am hoping that if I release the 14 pin connector, with Fuse #16 in place, the current drain will drop to 8mA  which would indicate the fault to be in the module itself & not the panel which is not displaying anything with the ignition off.  Here's hoping!

I think your logic is sound & you will be proved right, I have forgotten more than I learned about my MK1 Octavia but I have some recollection that these modules are exposed to the elements and can play up or fail.

 

Or it might have been another dream, so could this in fact!

The car is working again but I want to share two links to YouTube videos that I found helpful since the AirCon Relay Control Module seems to have more than one failure mechanism!  I didn't find other failures relating to excess quiescent current drain that I was experiencing, which I now believe was probably a stuck relay within the module itself, but there were several failures relating to the fans and overheating!  

 

The first stage of the repair was to remove the battery so that I could extract the two 10mm relay module holding bolts and twist it over to get the appropriate part number. The part number of my Relay module was 1J0 919 506 K and I managed to source a used one from eBay.  There were a number of after market new ones available but I wanted to use a genuine VW component as a few postings reported issues with Chinese copies. At this stage I decided that, since the two connectors were facing downwards and not easily accessible, to remove the battery shelf which is held in place with 4 highly visible 10mm bolts plus a 5th hidden one between the shelf and  the air filter box.  The connectors are hermetically sealed against moisture and are not easily removed but a YouTube video  https://www.youtube.com/watch?app=desktop&v=WSuR0RGUsr8 posted in America was very helpful in showing how to release the connectors. Once the connectors were removed, a further ammeter check, made with the battery temporarily connected with croc clip leads, confirmed that the current drain did indeed drop to ~8mA. The new module was fitted and another current check indicated the current stayed at 8mA before replacing the shelf and battery itself.

 

I would add that, since more failures of this module occur from heating/cooling/fan issues, another American YouTube video posted in the comments of the earlier one: https://www.youtube.com/watch?v=9Gx9TwohCXg is worth a watch. It is a long clip and the explains more issues than just the Relay Module which features towards the middle. Both videos illustrate that this particular module was widely fitted across a whole range of VW 1999 to 2005 group vehicles and seems to have a variety of failure mechanisms!

 

I hope this post my prove useful for others who are experiencing any of the range of issues that are associated with a failure of this module and would thank all those whose previous postings and comments that I have drawn upon to get my car working.

Nice work.