You donít need to jump any pins.
On the G4 you have 3 wires that are relevant to powering up/down the unit:
- Black: Ground or negative
- Yellow: +12V or Battery positive
- Red: Accessory or ACC or IGN
A General thumbs up when working with car electronics:
-DO NOT connect positive (black) to negative (red or yellow) current. Thatís how lightning is made.
Using ATX PSU:
On your ATX power supply that you have you will have some 4-pin molex connectors. Cut one of them off and:
- Youíll have 4 wires: 2x Black, 1x Red, and 1x Yellow. Use some electrical tape to isolate the ends of the red wire and one of the black wires.
- You will wire together (twisting the wires and using some electrical tape should do) a black wire from the ATX to the black wire from the G4
- You will wire together the yellow wire from the ATX PSU to the RED AND Yellow wires from the G4.
The one thing I will have to caution you about your ATX power supply is it might not turn on if you donít have it connected to a motherboard (so the G4 will not power on). I am not sure how much you know about computers, so Iíll explain it anyway. Pretty much if you have a 20-pin (or 24-pin) connector coming out of that ATX power supply that thing will not turn on unless that 20-pin (or 24-pin) connector is hooked up to a motherboard. There is a way around this where you cut the green and a black wire from that 20-pin connector and twist them together. This will trick the PSU into thinking that it is connected to a motherboard and it should power on your G4.
Using Desktop Battery/AC-DC brick:
An alternative to the ATX PSU option is to buy a 5A (minimum) rating AC-DC brick from Radio Shack. You can see on the back of the brick there is a DC rating and make sure it is at least 5 Amps (5A). Youíll splice the barrel connector on the DC (output) side. There will be two wires (probably a white shielded wire wrapped with a multi-stranded wire). Theoretically the white wire is the positive and the multi-stranded wire is the ground (also negative). TEST the wires with an Amp meter (or multi-meter) to make sure. You donít want to fry your $2k car computer.
Connect the ground from the brick to the black from the G4 (twist them and isolate with electrical tape). Connect the positive from the brick to the yellow and red on the G4 and isolate the wires.
So as you noticed thereís a common theme in powering up the G4 on a bench.
- You need to feed positive (+12V) power to the Red and Yellow wires on the G4
- You need to connect the ground (negative) to the Black on the G4.
Another thing that might be useful is the RED wire on the G4 is the Accessory wire. This is how the G4 knows when your car is on or off. If you remove this wire while it is connected to a 12V source the G4 will think you have turned your car off and it will go into stand-by.
If you have any doubts about this wait and talk to one of us. The ATX method seems a little harder but the wires are color coded (you know which is positive and negative) so you canít fry the unit. The AC-DC brick way you can mess up very easily if you havenít worked with a multi-meter before.