my rear window only opens when the hatch is open

Hi Jakeepoo,

Back Window is a must have working!
Agreed.

I had the board out and looked at it. All electronic parts and solders looked good from the outside.

There are 2 plugs into the board. A smaller plug that is providing power.
A red cable in the smaller plug was pulsing showing some Voltage on and off at all times (ignition was off). What might that be?
Again my car is a 2003 T4R , 8 cylinder.
If you can give me some hints on how to test this board I'l definetely do this.


Any help is welcome.

Thanks, Martin

Sounds like you have an issue within the circuit not the board. If you're getting pulsing battery voltage on the red cable. Check the circuit in sections. The boot that contains the wire harness from the body to the rear hatch is a good place to start your check as it gets wear and tear from all the motion. Also rear window hatch up and down relays. A bad relay could allow that pulsing power through. Check the grounds on the circuit. Also a faulty switch, bad contacts. Check from relays to back hatch. The mission is to find where the voltage begins pulsating in the circuit with your multimeter. Maybe try swapping out the relays with another of the same prong layout. I didn't look for a diagram, I'm too lazy, but you can find it yourself. This can all be done and tested with the multimeter and a test light if you have one but it's not necessary.

No diagram- Lazy Jakeepoo!

There are 2 boots at the top of the back door.... would you open both and check?

I have a multimeter and a test light, no problem.

Where are the 2 relays for the rear window located?
Faulty switch would be the window switch in the center of the dash?

I'll check all these components if I can find them.

(I have the T4R on the lift at the moment because if a bad brake system failure. Need to change the booster motor and accumulator. My dash lit up like a christmas tree the other day... the "bells" were not very nice as well)

I have no electrical experience but I can look around if I know where and what to search for.

Any hint where to find the el. diagram?

Martin

I bought the 2003 T4R Electrical Book EWD514U in order to try
understanding the electrical gremlin of my rear door. I have to say I am not an electrical engineer.... but I try my best to understand with my simple mind.

I think I found the red wire that had this weird pulsing (12V) at the smaller connector at the Rear Door ECU

The connector I am talking about is called B8(A) and it is connected to the
ECU. It has 4 wires at Positions 1,6,5,4. 1 is the red wire.
Disconnecting this plug B8(A) from the ECU will stop the clicking of the locks but also it will disable the rear door functions (window, lock etc).

Wires inside the Boot to the rear door are the problem?

Now the problem always get better during dry weather and it is becoming worse during heavy rains in summer....as Jakeepoo mentioned the rubber boot on the upper left side feeding the wires into the rear door might cause the problem as there are 4 wired passing through that are moving with each opening movement of the rear door..and wires might be rubbing against each other and cause a problem when wet. And this place is always wet in rainy weather with the car being parked outside (yes, no garage).

Door Relays
Jakeepoo said I should find the 2 rear door window relays (there might be a problem with them if the rear window is opening on its own....) But I still did not find the relays.
As far as I could understand all window and lock functions- and a lot more are part of the 'Multiplex Communication System'. In the book this is the blue ribbon on the diagram I show. I don't know what this blue ribbon physically is...probably a bunch of ECU that are connected by cables.
So where are the relays for the windows? I don't know. I see some external relays (for defog, horn, head light , stop light and dome light for instance) but not for window motors. Window motors are controlled by P11, P10, P12 ..called Power window control. Does this mean there are no ordinary relays for the windows... probably.

Best, Martin

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Ugh, I'm jealous you got the electrical section! I don't have this but I manage. You have everything there you need bud. Should be a few thousand pages at least. Look up the relay section.. it'll tell you where every relay is. There are relay junction points under the hood, driver and passenger side under dash. You'll just have to read until you find the complete circuit. It should be in there under a specific section for the rear window. If you find the complete circuit, every circuit should be in there, you can post that also. How did the wiring under the boot look? Sorry I take awhile I'm usually in the forest off road 👽

Here is a picture of the wires after pulling the boot at the rear door.
cables are looking good and there is no sign that something is bad.
Not sure what to do.

I did not find the 2 rear door relays. Please can someone help me finding these?

My only explanation so far: Rain water is running from the roof over the rear door and somehow the water is getting into the boot.... and this causes the problems. But maybe this is wrong and the problem is somewhere else.

Martin

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This. Apologies to the OP but if I had the wiring diagrams, this would be done. I'm just a few weeks into T4R ownership and have zero electrical problems. I don't have a need but I am going to order the manual anyways.

My best guess is hatch ECU or door control module is bad. If you have access to another ECU, swap it in.

Have you found the circuit diagram in your glorious electrical fsm? I would have already read that whole thing, I'd be so excited to have that! With the connector unplugged you could do a piercing probe right there to see if you're still getting pulsating battery voltage. And cover with some heat shrink for a quick test. But the proper way is to go up to the next junction point in the circuit and test there to determine which side of the circuit the issue is on. I doubt its bad but in your magestic electrical fsm there will also be a section dedicated to that rear window ECU. It'll tell you specific values and how to test it simply with your meter... that rear window is a must have. Post the circuit if you need more specific help. 👽