I'm just looking through the manual for my new Alpine HU before I go and install it and in the section about the Dimmer function (to dim the stereo display using the car's illumination circuit) it states:

"If your vehicle should have a dimmer control for the dashboard lights, never connect the DIMMER cable of the radio to this dimmer control."

As this is not mentioned specifically in the Installation section of the manual, I'm not quite sure what it means, and as my Octavia has got the dimmer dial for the dash lights I want to make sure I get it right.

Does it mean I shouldn't connect the stereo to the car's illumination circuit at all, or that I shouldn't try and connect it to actual dimmer control dial (which I wouldn't have tried to do anyway :s)?

the octy does not have one in the standard wireling loom for the HU i belive what that is refering to is dont connect it to the twiddly knob that you cna use to dim the speedo display lights..

Joel

Well, I fitted the HU last night, so that's one more job out the way. There's not a lot of room behind that dashboard for the extra cabling! It was well worth taking the glovebox out to get better access, and even then I'm glad I've not got big hands.

There is definitely a wire on the main loom that connects to the same pin as the illumination wire on the harness adapter, but maybe it serves another purpose if you think there isn't one for illumination. Normally I'd check the wiring diagrams in a Haynes manual to be sure, but they don't do one for the Octavia yet.

I didn't connect it upin any case, just set the function to manual. To be honest, even in daylight the HU is bright enough to be seen well enough even whilst dimmed, so I reckon I'll just leave it as is.

Next job is fitting the changer in the boot in place of the standard one, when I get chance.

I had an issue with my replacement HU. When the dashboard dimmer switch was on anything less than full brightness, the display on the HU would flicker on and off. Apparently the HU display takes its supply from the dashboard dimmer, and at full brightness gives 12V. Less than full brightness gives less than 12V, therefore may cause problems.

Not being much of an electrician, this may be totally useless info, but my HU display behaves ok when the dashboard dimmer is at full.

I wonder if the in-car dimming is PWM? This would work fine for the bulbs in place, but not so well for a device that is expecting 12VDC. There's certainly some degree of electronics in there, as you can always see a slight delay between moving "the twiddly kn0b" and the dash brightening / dimming.

Edit: Oh dear. :( The profanity filter is working overtime ... I hope no-one minds my blatent attempt to bypass it in this case