Anyone wired their Alarm/CL to the Hazard Lights?

LogIK · Post by **LogIK** » Thu Jun 17, 2004 5:54 pm

Right, I'm having a bit of a problem with my wiring. I've decided to do a few jobs today, and one of them was getting the indicators working with my central locking so that when it is armed/disarmed, it will flash the indicators.

I have two wires coming out of the central locking 'brain' to flash the indicators. At first, I thought that one would be for the left side indicator and one would be for the right side, but from testing it, if I attach each wire to each side, only one side will flash. If I reverse the wires, the other side will flash, which leads me to think that one wire from the central locking must be live, and the other must be earth, rather than being two lives to flash both sides simultaneously.

Now, in my mind, the only way to get both sides to flash is to tap the central locking indicator live into the hazard feed and earth the other one. This way, each time the realy switches in the central locking, it will put 12v across the hazard feed and illuminate ALL of the indicators.

My problem is finding the live feed for the hazards. I've studied the Haynes wiring diagram and it seems that there is not seperate feed for the hazards, but there must be!!

If anyone has any ideas, they will be greatly appreciated. Thanks.

LogIK · Post by **LogIK** » Fri Jun 18, 2004 2:21 pm

Here's my solution up to now:

However, there is a potential problem with this. Since it is constructed in parallel, it will have to draw twice the current for both the left and right circuits, which may overload the central locking ECU.

Anyone have any suggestions

david burton · Post by **david burton** » Fri Jun 18, 2004 2:26 pm

yeah i was going to suggest this - just split up the 12v signal into each indicator circuit.

I doubt it'll blow a fuse? if you suspect this, then use a relay...

if the bulbs are 2W, then the current is 0.17A to each side - hardly enough to blow fuses...

let me know how it goes.

LogIK · Post by **LogIK** » Fri Jun 18, 2004 2:37 pm

Since the ECU already has relays built into it, which create the pulse, rather than transistors, it should be okay.

I'll give it a try and let you know how it goes.

Thanks.

GroovyCarrot · Post by **GroovyCarrot** » Fri Jun 18, 2004 5:27 pm

It's going to draw the same amount of current wired in parallel as it is wired in series. Same number of bulbs, same resistance, same voltage being applied. All this means is that the current will be divided evenly between the bulbs. I wouldn't worry about it blowing fuses either, indicator bulbs are hardly the most powerful things in your car

LogIK · Post by **LogIK** » Fri Jun 18, 2004 6:27 pm

Okay, I just went down to Maplins and bought two 12V 6A inline diodes (cost 10p each) and wired them is as shown in the diagram. I'm glad to say that it works a treat without any problems.

So, if anyone needs to do this to their alarm or central locking but was faced with the same problem as me, then there is your answer.

Jobs a good 'un.

david burton · Post by **david burton** » Fri Jun 18, 2004 8:21 pm

nice one!

are the diodes to stop the central locking receiving current when the indicators are on normally?

LogIK · Post by **LogIK** » Fri Jun 18, 2004 11:53 pm

No, the diodes stop a short circuit occuring between the left and right indicator circuits. Without the diodes, it would still function fine, except when I come to use my indicators. I would find that activating either left or right on the stalk would cause all of the indicators to flash! They prevent current from flowing back and through the splitter into the other circuit.

david burton · Post by **david burton** » Sat Jun 19, 2004 12:07 am

now i get ya - nice one!

DanW · Post by **DanW** » Thu Jun 24, 2004 3:49 pm

for later reference which relay or point on the ECU is the indicator input connected to ?

LogIK · Post by **LogIK** » Thu Jun 24, 2004 5:27 pm

Huh? The indicator INPUT? The ECU has an indicator OUTPUT in order to perform a switching live circuit which gives you the flash when you arm/disarm.

DanW · Post by **DanW** » Thu Jun 24, 2004 7:29 pm

whoops! i meant output lol sorry

are the connectors labeled?

LogIK · Post by **LogIK** » Thu Jun 24, 2004 8:22 pm

There is one wire for the indicator output. On my unit, it is brown and is labeled on the unit's wiring diagram. Many have two wires for the seperate left and right indicator circuits, but this was the problem that I was having, before that diode circuit was made.

The wires are usually never labelled, you have to follow them on the wiring diagram, which is just as easy to do.

Why you ask? Are you installing central locking or something?

DanW · Post by **DanW** » Thu Jun 24, 2004 11:43 pm

as soon as I can get hold of a kit yeah. Because I keep forgetting to lock my doors and always go round to the passengers door and check it even if I ushualy trust the passenger lol

LogIK · Post by **LogIK** » Fri Jun 25, 2004 10:13 am

Yeah, must agree with you there mate. I was always forgetting to lock my door and so were passengers. Remote Central Locking is a really good mod to do, coz not only can you unlock all your doors (and boot) with the push of one button, but you lock/unlock all doors from the inside, so you don't have to keep leaning across to let a passenger in and you can also de-lock, which looks much neater on the Polo.

You should have no problems installing it Dan. Don't worry about what wire is what, coz it differs between kits and it all labelled on the wiring diagrams anyway. The hardest part that I thought was getting the windows to clear the motors (ie not hit them when I wind the window down.)