HU Power wiring help!

[12ORY]

Okay, I just tried to install a new alpine 9857R HU however I'm having problems getting the unit to work with the key out of the ignition. I have used the alpine loom and connected the yellow wire with the in line choke coil to the yellow wire on the the iso connector which connects to a +12.5v OEM wire already in the clio. The red ignition wire is connected to the red ignition wire on the iso connector which I have tested is 0v when the key is out but switches when the key is turned. I cannot however get the HU to operate with key out! Can anyone shed some light as to what I'm doing wrong? Does the unit require more than 12.5v to operate? The unit retains radio stations when the key is removed suggesting that it does have the constant power wired correctly.

 

[Da]

what car is it? The clio's (Mk2 ph2) do not have power once key is switched off/removed. The only way to make the stereo work with the ign switched off would be to connect the switched +ve to the permanent +ve feed. ie both the red and yellow cables to the permanent +ve.

 

[Dink]

you need to apply power to both the red and yellow cables.

if it is a 4x60w unit you need a seperate supply cable and NOT to use the oem wiring

 

[12ORY]

The unit is a 4x60w HU. Does that mean to power it it without the key you require two constantly live inputs (yellow and red)? I'm unsure exactly why you should not use the oem wiring - unless you require two constant live wires.

 

[Dink]

as the unit is capable of pulling more current than the oem wiring can take.

or were the yellow and black part of the alpine to iso wiring adaptor that came with the hu

 

[12ORY]

I already have a previous live feed direct from the battery so there is no problem using this. Which wire should be connected to the oem wiring then? The red or the yellow or are both not capable of pulling the required current?

 

[12ORY]

The loom that came with the Alpine HU is fully wired to the iso block but previous alpine looms had a seperate earthing point instead of being wired to the iso block. Surely alpine would not do this if they really meant for a separate earth and power supply to be taken from outside the oem wiring??

 

[Dink]

if you have already got a perm at the hu thats is capable of supplying >20A

then to get it to work with the key out you need to connect both red and yellow to this

 

[12ORY]

Right so I tried connecting two constant lives which solves my problem. (Cheers for the help dink!) However I still don't understand. The unit clearly needs two lives to operate which seams strange. As for the increased current load. The wire on the loom supplied from alpine has a thinner red wire than the constant live in the oem wiring for the clio. Therefore any posssibility that the wires cannot cope with >20A current would be more of an issue from the iso plug in the clio to the back of the HU and not the original oem wiring i.e. the battery to the iso plug! Anyone explain?

 

[Dink]

the red is the switch wire needed like a remote for an amp pulls no power just voltage sensing

the yellow is the one connected to the amps in side the hu and will pull 95% of the power

 

[12ORY]

Ah, I see cheers Dink.

 

[Dink]

no probs

 

[12ORY]

Right more questions...I previously had my old alpine unit wired so that when the key was withdrawn, the hu would switch off but could be switched back on my pressing the power button when the key was out. Now, with the wiring described by dink, the unit is constantly on even when I withdraw the key and needs to be manually switched off. The reason I wish the unit to be wired the same as I previously had is in case the unit is left on by accident and runs the battery of the car down. I do however wish to have the option of turning the unit on without the key though. Does anyone know what I've done wrong or how this can be done?

 

[jamesy]

the yellow wire must be connected directly to the battery matey under no circumstances must you connect it directly to the dash the red is a switched power and you should have a seperate earth the unit can easily be wired up with an iso block or without if you join the yellow wire with the red you will not be able to operate the unit off the ignition as it all be constantly live