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Electric windows failed down!


ChelseaTractor

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The boy put the front window down in our new (to us '04 Disco 2) to wave goodbye to someone today and now the bloody thing won't go up or any further down.

I've checked the fuse, it's ok and traced the clicking back to the ECU under the glove box. I've wiggled the wires and taken out and replugged in the connectors with no joy. The rears work fine, it's just both the front windows.

Any ideas what's wrong before I replace the ECU?

I've now got to take the door card off and run a feed to the motor to get the window up. Deep joy. :(

Jon

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So, the window is now up after direct feeding the motor. The Switches work too.

After searching and googling for two days I now know that the fault lies with the BCU. Ok so I buy one from a breaker and fit that....

Only i can't because they are coded with the key and will not work without re coding. :angry:

I read that the BCU would sometimes reset if the battery lead was off for 5 mins. If that wasn't a wind up it didn't work!

Now I'm confused and don't know the next step. A figure of £2500 was mentioned on one site for a new Valeo BCU and 2 key fobs correctly coded. :(

Could I do the job myself with NANOCOM? I know nothing about this either.

HELP!!!!!

Jon

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Spoke to an old friend today who owns an indie.

He had a chat with his electrician who said he would be very surprised if it was a fault with the BCU.

He has advised me to throughly check everything again, relays, wires etc.etc.

Would anyone be able to post a wiring diagram of the front window set up showing relays or point me in the direction of somewhere that I could download one.

Cheers

Jon.

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use a multimeter and check the wiring connection where it goes into the door from the A pillar, it could be a broken wire in there.

as you say you can hear clicking from the window ecu, it's more than likely a broken wire.

is it just the one window, or both/all?

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There are no relays in the circuit.

On the front windows, the BCU operates the window motors directly, by applying a live and earth on the two wires to the motor, then swapping over the live and earth on the same two wires to operate the motor in the opposite direction.

The window switches only provide an earth path to wires from the BCU, which signal it to operate the windows in the selected direction.

Here's the diagram -

th_FrontElectricWindows2003MY.jpg

And the relevent bit expanded -

th_FrontElectricWindowsexpanded2003MY.jpg

As disco_al has said, your fault is more than likely where the wires go from the pillar to door.

The rear windows don't use relays or the BCU, they're switched directly by the window switches, which are double pole changeover switches.

.

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There are no relays in the circuit.

On the front windows, the BCU operates the window motors directly, by applying a live and earth on the two wires to the motor, then swapping over the live and earth on the same two wires to operate the motor in the opposite direction.

The window switches only provide an earth path to wires from the BCU, which signal it to operate the windows in the selected direction.

Here's the diagram -

th_FrontElectricWindows2003MY.jpg

And the relevent bit expanded -

th_FrontElectricWindowsexpanded2003MY.jpg

As disco_al has said, your fault is more than likely where the wires go from the pillar to door.

The rear windows don't use relays or the BCU, they're switched directly by the window switches, which are double pole changeover switches.

.

Cheers Guys. Guess I'm now going to have to trace wires. A job next to emptying tabasco sauce on your eyes in the 'most hateful things to do manual'. :angry::angry::angry:

I'd dismissed this as neither of the fronts are working.

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