e39: need to find a +12v high beam trigger

[rogan 1]

Going to hardwire my gate remote into the e39 and use the high beam to activate it. Will be using a constant to momentary output circuit like this one: http://www.the12volt.com/relays/page5.asp#ctm

Anyone know where I can easily tap into a 12V+ highbeam that won't give me error messages about blown bulbs etc?

Thanks

[jochen 4]

Going to hardwire my gate remote into the e39 and use the high beam to activate it. Will be using a constant to momentary output circuit like this one: http://www.the12volt.com/relays/page5.asp#ctm

Anyone know where I can easily tap into a 12V+ highbeam that won't give me error messages about blown bulbs etc?

Thanks

Easy.

Firstly, note that the high beam switch switches a 5V line to ground. The 5V line goes to the Light Control Module (LCM). So if fitting a relaz here, zou-ll need a blocking diode to prevent backfeeding 12V into the LCM data inputs.

The LCM then switches on the power to the high beams>

White with green stripe wire is left high-beam

White with blue stripe wire is right high beam

Wires run from LCM in driver's footwell to the bulbs.

This is the only way to tap into the high beam light circuit.

You cannot use the instrument cluster as the high beam is an LED controlled by data transmission over the databus

[rogan 1]

I wasn't sure if I was going to need a blocking diode but was going to whack one in just in case.

Woud I need a 5v relay like this one http://www.dse.co.nz/dse.shop/4a9dac82008e...duct/View/P8005

or can I use a normal 12v relay (guessing 12v won't work)?

Just re-read your post, so the wires from the LCM to bulbs are 12v and this is the place to tap into them.

Thanks heaps

Next question, is it the same sort of set up in an e46 cos I'll probably do the wife's car too

Edited September 1, 2009 by rogan

[jochen 4]

I wasn't sure if I was going to need a blocking diode but was going to whack one in just in case.

Woud I need a 5v relay like this one http://www.dse.co.nz/dse.shop/4a9dac82008e...duct/View/P8005

or can I use a normal 12v relay (guessing 12v won't work)?

Just re-read your post, so the wires from the LCM to bulbs are 12v and this is the place to tap into them.

Thanks heaps

Next question, is it the same sort of set up in an e46 cos I'll probably do the wife's car too

Use the 12V feeds for safety.

The E46 is very similar, but the Light Control Module is directly behind the light switch (pull light switch out to observe)