Engine out, need to lower roof.

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chu346
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Mon Aug 22, 2016 3:15 pm

Hi, I'm doing a V8 engine swap, currently the engine is out and won't be going in for a while. I now need to lower the rear windows to lower the roof. I tried connecting the battery to the fuse box wire and earth but the car is dead. How can I connect the battery to power the windows?

Car is 1992 318i cabriolet

Thanks
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e30-unit-soldier
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Mon Aug 22, 2016 3:59 pm

I'm assuming it's a electric roof?
You can lower it manually by disengaging the 2 roof motors
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chu346
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Mon Aug 22, 2016 4:59 pm

Thanks, I know how to do that. I want to lower the windows.
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andysheep
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Mon Aug 22, 2016 5:12 pm

Door card off fumble about inside bottom of door find power conecter for window motor 12 volt battery one way up one way down,rear windows look for same conector behind rear side card (bugger to get out ,take your time )make sure its goin throu to window motor first and samedeal as front :D
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chu346
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Mon Aug 22, 2016 6:06 pm

I was hoping for an easier way.

Isn't there a way to simulate the engine being in by connecting a circuit?
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e30-unit-soldier
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Mon Aug 22, 2016 6:15 pm

I had a total closure alarm in my cab years ago and it was wired to each one of the window switches...
You might be able to run power through them? But please do your own research and don't blame me if your car gets goosed :P
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chu346
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Mon Aug 22, 2016 6:33 pm

I guess 12 volts to the correct switches could work
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Brianmoooore
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Mon Aug 22, 2016 8:05 pm

Find the green/black wire that went to the starter motor (smallest ring terminal), and temporarily connect it to a good body earth, OR remove relay K5 and link together pins 30 and 87 of its socket with a piece of wire.
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chu346
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Mon Aug 22, 2016 9:51 pm

That's the answer I was looking for, thanks
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chu346
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Wed Aug 31, 2016 3:19 pm

Brianmoooore wrote:Find the green/black wire that went to the starter motor (smallest ring terminal), and temporarily connect it to a good body earth, OR remove relay K5 and link together pins 30 and 87 of its socket with a piece of wire.
interior lights came on, but windows didn't work :?
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Brianmoooore
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Wed Aug 31, 2016 6:08 pm

What interior lights???
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chu346
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Wed Aug 31, 2016 9:15 pm

The interior light connected to the door switch. Wipers also worked.

I shorted the pins under relay k5 because I don't have the other wires.
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Brianmoooore
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Wed Aug 31, 2016 9:58 pm

Interior lights should work anyway, and wipers as well, when the ignition is on, regardless of whether there's an engine in the car or not.
Sure you found relay K5?
Come to think of it, just opening a front door should make the windows circuit come to life on European/UK E30s. No need for any relay shorting on green/black earthing.
Which wire did you connect to the battery +? It's one of the red wires bolted to the terminal that goes to the fusebox, not the big wire permanently attached to the terminal clamp.
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chu346
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Wed Aug 31, 2016 10:10 pm

When I took the engine out all the wiring went with it. I'm left with the fuse box wire that goes directly to the battery.

I looked at the fuse box lid to find relay K5.

What do you mean terminal clamp? The ground near the battery?
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Brianmoooore
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Wed Aug 31, 2016 11:12 pm

Terminal clamp is the bit with the big round tapered hole that fits onto the battery terminal.
This clamp has the big wire that goes to the starter motor permanently attached to it.
Bolted to the clamp will be a red wire that goes into the engine loom, a red wire that goes to the fusebox, and depending on spec., a red wire that goes to the ABS pump.
From what you say, the only one you have left is the one the fusebox, and if you refit the battery, connect the negative clamp to the negative terminal and the red wire to the positive terminal, the car's body electrics should power up, with the exception of those that are fed by the two unloader relays, K5 and K7.
You say the interior lights and wipers work, so you have correctly connected up the battery.
Relay K5 feeds the windows (and heated seats, if fitted), and K7 feeds the heater fan and electric mirrors. Both of these relays can be bypassed by linking 30 and 87 of their sockets, and if you do so, all body electrics, including the windows, should work, with the exception of a couple of engine warning lights in the instrument cluster.
As i belatedly remembered, on UK E30s, the windows will work with the ignition off and a front door open.
Do the window switches light up when you connect the battery and open a door?
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