Hi

 

Been searching on here for a while for some info on how to test the wiring in the driver door with a multimeter. I know how to use the meter (I've used it to do things like diode testing the alternator and voltage drop on fuses).

 

I've just never done testing on wiring like this before. I've taken the door apart because the window won't operate. I don't think it's the switch panel because some of the other switches work. I'd like to be able to test the various connectors for voltage before i go replacing motors and the like (This door is just the start. The passenger door is ignoring the central locking, the rear right window wont go down, the heated rear window doesn't work).

 

I just can't find a guide for it anywhere so i'd really appreciate it if someone could point me in the right direction. 

Pretty much all you can test is the main live and neutral to the door controller, none of the switches pass the current of what they operate but instead communicate with the door controller which drives the lock mechanism, window, mirror etc and communicates with the comfort control module and the other door controllers via the canbus network.

 

You should look for water ingress to all the door controllers which is the main connector to the electric window, you can check the door looms for continuity, you should check carefully all the wires inside the door bellows for fractures especially the drivers one and also check for water ingress/corrosion on the comfort control module.

 

If you have access to VCDS it will almost certainly tell you which module is not communicating or which door microswitch (something else to check) is open circuit or implausible signal, it really should be your first step & will save you loads of time.

 

I had the same problems culminating in all doors remaining deadlocked except the drivers door, I ended up scrapping the vehicle which I regret, had I bought VCDS I would not have needed to.

Edited 2 March, 20206 yr by J.R.

Testing the wiring in the door involves what is called a continuity check, which essentially means you are looking for either a loss of an emitted tone on your meter when it as applied to both ends of the cable that you are testing, or a change in the displayed reading if your meter does not emit a tone.

 

You basically disconnect the relevant plugs on the end of the loom you wish to test, then apply one probe into the plug onto the particular wire you need to test (i.e. blue wire with a white trace) then place the other probe on the same wire in the plug at the other end of the loom. if the wire is unbroken, your meter should emit a beep tone to let you know you have continuity, if you don't get a beep, you have a broken wire. I always move the loom about even if I get a tone, in case the wire breaks when moving around - like when you open the door, just in case the wire may not have completely broken yet. If you find a lot of corrosion, you can use the resistance scale on your meter to see how bad you issue is in the wire itself.

 

Youtube have quite a few vids if you put in continuity check to let you see what I mean in greater detail.

 

Hope it helps.

 

Phil

Hi

 

Thanks for the info chaps it's set me on the right path.

 

As it happens i'd already arranged for a friend to come over and do the vcds thing.

 

Loads of faults! Lol!

 

Not sure what i need to redact here so i'll just post the fault list for now. Its from Address 19: CAN Gateway

 

8 Faults Found:
01336 - Company Data Bus for Comfort System 
            37-10 - Faulty - Intermittent
01336 - Company Data Bus for Comfort System 
            49-10 - No Communications - Intermittent
01330 - Central Control Module for Central Convenience (J393) 
            49-10 - No Communications - Intermittent
01304 - Radio 
            49-10 - No Communications - Intermittent
01331 - Door Control Module; Driver Side (J386) 
            49-10 - No Communications - Intermittent
01332 - Door Control Module; Passenger Side (J387) 
            49-00 - No Communications
01333 - Door Control Module; Rear Left (J388) 
            49-10 - No Communications - Intermittent
01334 - Door Control Module; Rear Right (J389) 
            49-10 - No Communications - Intermittent

 

Thing is the doors aren't dead there's stuff on all of them that works. Was wondering if the software was testing for something my car doesn't actually have?

 

 

 

Dont overthink it, there is a problem with the canbus communicating between the modules, it will probably be one of the things already metioned,

 

1st thing check very carefully the wires inside the drivers door bellows for signs of breakage, flex them all as the insulation might be intact hiding a fractured conductor, usually its plain to see the broken wire.

 

2nd Remove the connector from the drivers door controller, are there signs of water ingress, oxidised connectors?

 

3rd Check the drivers door lock microswitch, that you can do with your multi-meter

 

4th Check the Central Convenience/Comfort control module, is the cabin damp indicating water ingress?

 

Finally do steps 2 & 3 for all the other doors.

Looking at those code numbers, I would probably expect to find loads of green corrosion on the drivers door module connector block.

 

I bet if you remove the connector at the moment with this wet weather, a load of water will drain from the module.

 

The mk1 Octavia is only partially Canbus, and usually, corrosion issues send the canbus into single wire operation mode (the default is paired mode)

 

Check this out, as it has good info for you -

 

 

Thanks guys

 

Bit of a learning curve here!

 

I didn't have much time last night but i did have a look at the door module and it looks ok i think. I didn't see any corrosion or anything. I took what i think must be the door module off the motor (It was held on with a weird combination of metal straps and clips) but it looked ok inside as far as i could tell.

 

I'll do some more investigation over the next few days.

 

Thanks for the help so far all. I'll be back!

Did you actually separate thr connector from the module?, or just remove the module from the window motor?.

 

I would start moving back down the loom so you dont miss any connections if the module connector was clear,

 

Base of the A post is the next connector, then the CCM is next.

 

As J.R also wrote, it is more likely to be a connector/broken wire in line to the drivers unit than the others as only the drivers door has universal control of the other 3, the others are just isolated in that respect., apart from the canbus signal wires to all modules.

 

When you do find the fault, protect all the disturbed connections with non-conductive silicon grease so that you considerbly reduce the chance of the fault returning.

Hi

 

I removed the module from the motor and the connector from the module too. It all looked like it was in good shape to me.

 

So I had a faff with the car after work. I'm still trying to get to grips with wiring diagrams so I guessed a bit.

 

Tried to test the module connector for power. Assumed the bright red wire was power but it had no voltage. Tried back probing and in the connector with the ignition on but nothing.

 

Tested the pool light connector too just to see and it had nearly 12 volts. I think I did that test right.

 

I also connected the switch and the module and motor and when I pressed the window switch I could hear a click from the module like a relay. Maybe my attempt to test for power in the module connector was flawed.

 

Also tested the connector for the wee controls that work the mirrors and again no power.

 

I'll see what's behind that A pillar tomorrow.

 

Thanks for the help so far.

 

 

Just to rule out the really obvious, I take it all your fuses are intact?

Hi

 

I'd looked at them before and thought they were fine but i just tested them all with my multimeter and found one that doesn't register.

 

F6 - listed as central locking control unit in my Haynes manual

 

However, the central locking was working on all the doors except the left front.

 

I've swapped it with the glove box light one to see if it makes any difference to the other issues. (Did it in the work car park so no spare fuses)

 

I spent ages last night learning about wiring diagrams so i think i've a better idea how to test the loom now. I'll give that a shot later.

 

Cheers