Digital Climate Control Glitch

[GRSHOPR]

OK, so I just (mostly) finished doing a digital climate control conversion in my 94 base 3000GT, but I'm having two hiccups. First, I finished with two spare wires out of the computer, plug C-49, one is R-B (red and black tracer) and the other is Y-R (yellow with red tracer). Does anyone know where they run to? The display resets itself every time I turn off the car back to base settings, so I'm guessing one, or both of those wires plays a role in that. The other issue is, I can't get the back lights on the display buttons to light up. I removed the original bulbs, and installed some LED's in their place, with the proper resistors and all for a 12V source. I initially thought I traced the lines backwards, but after swapping the polarity, still nothing. Anyone have an answer for that one? I'd prefer to just hard wire them to an ignition source and be done with it, since the rest of the dash lights are constant on too. Can anyone shed some light on this? Thanks.

[GRSHOPR]

OK, I think I managed to trace the wires, and I'll take care of those tonight, but anyone get why the back lighting isn't working? Or of a way to permanently rig it on?

[DrGonzo]

Try swapping out to the original bulbs and see if they work. Might be an issue internally with the display unit itself.

[GRSHOPR]

And what if, say, the bulbs are already gone?? Haha, already chucked em weeks ago. But it seems like the problem exists prior to that. If I'm reading the schematic correctly, and I'd like to think I am, there should be power flowing through the photo sensor, to trigger the backlighting, but both wires for the sensor are dead.

[GRSHOPR]

OK, so the memory issue is definitely fixed, which just leaves the backlighting. I removed the LED's, just in case, and tested all four contact points (2 for each of the 2 bulbs slots), and there is no power to any of them. Is there a way to bypass the photo sensor altogether, and run the lights constant on, like I do with the rest of my dash? If you look at the schematics for the photo sensor, it comes from the climate control computer, routes straight through C-15, and onto the photo sensor. I bypassed C-15 altogether, and just spliced the sensor right into the computer, if that helps. There is also no power to the photo sensor, from either lead. Anyone got an answer for this? Thanks in advance for your help.

[Badandy247]

I disconnected my photo sensor on accident months ago (actually forgot about it till I read this thread), it doesn't control the back lighting of the panel. The photo sensor is intended to work in conjunction with the interior temp sensor to achieve the climate control function.

Was the ACC unit you are installing confirmed good before attempting to install. A common issue of these units is that the backlighting will fail but the unit will continue to function, some have been able to trace it to bad caps much like the factory ECU caps that die with age.