Added Pioneer, now A/C head won't dim?

[CutLoose]

I've searched but can't find an answer, Help please? I put a new(old) pioneer CD player in my 93 vert, it's so old it's "XM Ready" But now the A/C (auto climate) green display is so bright at night I can't stand it. All other backlighting normal. Any idea how to fix this?

[ManicMechanic]

The VF dimmer for the A/C control is run through your original stereo...Once you change it to an aftermarket, the dimming goes away.

[rockfangd]

x2

[mra32]

Inline dash mounted potentiometer?

[GnatGoSplat]

Potentiometer won't work. It has to have a PWM output. I used a simple 555 timer IC circuit with a potentiometer to control dimmed brightness.

 

[IRONDOG442]

install a rheostat !

[BXX]

You should be able to take the VF dimmer that goes to the radio plug, and splice it with the one that goes to the HVAC unit.. Its the same signal, just for some off reason GM decided to run it to the radio, and out another pin and to the HVAC unit..

[GnatGoSplat]

Rheostat and potentiometer is the same thing.

 

VF dimmer to the radio and HVAC unit were not the same signal, at least not on my '89. If I recall correctly, trying to connect that signal to the climate control dimmer input caused the screen to go blank with the headlights on.

 

It needs a digital PWM signal whose frequency controls the brightness.

 

[IRONDOG442]

it would have to work if you wired a rheostat in, its a simple matter of longer wire=more resistance , less current=thus dimming the lights

 

FTR I typed rheostat with an H I dont know why it didnt shop up!!

[GnatGoSplat]

Nope, resistance won't dim the lights. The dimmer input wire is digital. I think it's positive triggered, but I don't remember for sure. Anyway, if I'm right about it being positive triggered, you send it any voltage at all, and I mean any voltage, it turns the screen completely off. You leave it 0V, the screen stays full brightness. So to dim the display, you have to send it pulses. This pulses the display on and off so fast, to the human eye it appears to be dimmer or brighter depending on the frequency. This is how the digital dash and DIC displays are controlled internally. The climate control just doesn't have any kind of analog-to-digital converter inside.

 

With a rheostat, you're going to get the display either completely off or full brightness, no in-between because it's not an analog input.

 

[IRONDOG442]

I hate you and your electrical knowledge, Physics II was my bitch !!

[mra32]

http://www.allelectronics.com/make-a-store/item/MK-804/DC-TO-PULSE-WIDTH-MODULATOR-KIT/-/1.html

[w-bodys_are_the_best]

I shouldn't ask this on the W board, but my 96 Park Avenue Ultra does the same thing, would you wire that controller in the link between the illumination wire and the ECC unit It's actually not that bad in my PA, I have an el cheapo pioneer in there now that doesn't dim, so it doesn't bother me, but plan on putting something better in sometime soon.