Wiring headunit to switch?

MGrove03 · Post by **MGrove03** » Thu Mar 20, 2008 8:12 pm

I recently installed my alpine headunit with bluetooth adapter which works brilliantly. The only problem is that when i switch my engine off the headunit and bluetooth adapter don't switch off. This is a bit of a pain as i have to remove power cables from the bluetooth adapter so it doesnt drain the battery.

So i managed to get a rear heater screen switch from a local scrap dealers and was wondering if it would be possible to wire up my headunit and bluetooth adapter to this so that it would act as a sort of 'kill switch' so all i have to do is push the switch to turn it on/off.

also if you can tell me what each of the wires is for on the rear heater screen switch that would be great

sylvester · Post by **sylvester** » Fri Mar 21, 2008 1:48 pm

What year of polo and HU model? Vw use a different wiring system than the standard iso, usually there is an option on the HU wiring to swap the ignition and battery leads over. How did you connect the HU wiring?

Post by **alexperkins** » Fri Mar 21, 2008 7:48 pm

Just put it on a SPST relay that operates on the ignition live. Thatll solve all your problems

MGrove03 · Post by **MGrove03** » Sat Mar 22, 2008 11:59 am

and where will i find an ignition live??

sylvester · Post by **sylvester** » Sat Mar 22, 2008 2:15 pm

Much easier fixing the HU wiring than adding a relay and a switch

Post by **alexperkins** » Sat Mar 22, 2008 6:59 pm

lol the HU wiring fix usually only fixes the memory effect problem that some newer HUs face. Its worth a shot tho

Ignition live is on the back of the HU on the black block. its the Red/white chunky one

If you want just a trigger then its the blue grey one

sylvester · Post by **sylvester** » Sun Mar 23, 2008 2:00 am

So far hasn't confirmed HU or model year but,

lol the HU wiring fix usually only fixes the memory effect problem that some newer HUs face.

Does that mean the proposed fix by MGrove03 is the norm for aftermarket HU on veedubs

MGrove03 · Post by **MGrove03** » Sun Mar 23, 2008 7:00 pm

its a 55 reg mk7 polo and i think it may be an alpine 9885r ive fitted quite a recent model anyway.

sylvester · Post by **sylvester** » Sun Mar 23, 2008 10:18 pm

If the rcd200 was originally fitted, this lead will solve your problem, autoleads PC2-75-4, get it on ebay, you may also require an aerial amp (PC5-136) if the radio reception is poor. For the illumination/dimmer you will need a feed from the light switch or heated window illumination.

How is the HU wired at the moment?

MGrove03 · Post by **MGrove03** » Mon Mar 24, 2008 3:37 am

i dont know what was originally fitted but the cars an 's' model if that helps. im currently using that lead to connect it also.

sylvester · Post by **sylvester** » Mon Mar 24, 2008 8:13 pm

Just noticed you've already asked for help in this forum regarding the HU wiring.

3 choices,

If the car has a large black connector autoleads PC2-75-4 adapter

If the car has 2 connectors, 1 black 1brown :autoleads PC2-69-4 adapter

or modify the HU wiring as follows,

if the car has 2 connectors, 1 black 1 brown, using the HU wiring switch the yellow(9) to the red(6) that has the twin connectors then remove the red (6)HU wire from the twin connector and join it to the yellow (9), so the wiring is yellow to red.

Look at the wiring in the manual

Aerial adapter either autoleads PC5-136 or PC5-52 , all got on ebay.

MGrove03 · Post by **MGrove03** » Mon Mar 24, 2008 8:40 pm

as said in my last post im using the pc2-75-4 adapter but it hasnt solved my problem

sylvester · Post by **sylvester** » Mon Mar 24, 2008 9:51 pm

im currently using that lead to connect it also.

Doesn't tell me a lot.

Do you have a test lamp?

What you need to do is check the blue, yellow and red wires to see which one switches on and off with the ignition.Whatever wire it is, this should be in the same position as the red wire on the HU connector, then the permanent +12v should be in the same position as the yellow wire on the HU connector. Some pc2-75-4 adapters have the option of changing the wiring over similar to the HU.