[nogard]

I'm going to be wiring in my MPGuino the afternoon. I've read some of the concerns with overheating. I never thought that would be an issue. But when you scale it down it makes sense.

I'm going to be installing this on a 1988 camry with 4 cylinder (3S-FE). I put an aftermarket illuminated vacuum gauge in. To get the back lighting to work on the with the factory controls I had to connect the positive and negative of the gauge reversed, I guess there was no diode or this would not have worked. Since the vehicle circuit uses constant positive and the rheostat is controlling current through the negative. This works great.

Now how do I integrate the LCD to the vehicle back lighting circuit. I would have to use this same reverse wiring to make the dimmer part work.

I just found out I can't post images, because I have a low count of posts. I will try to explain what I want to do in text and maybe later post a picture.

1. Is the power transistor on the upper right of the circuit with the 220 ohm resistor?

2. Do I need to disconnect all three wires from it? Or just the orange one feeding down to the LCD?

3. What are the pins on the LCD for the back light? (The one that the orange power transistor went to? and the ground next to it?)

4. If there is a separate back light ground then I could run that through the rheostat?

5. I also read about needing a 270 ohm resistor on the power off the vehicle backlighting (illumination) circuit?

Thanks.