Yeah ! I purchased one of the ashtray pods with the volt, oil pressure and oil temp. Man I must have some electrical problems I can't find. I tried wiring it up about a year ago and with no resolve none of my gauges work. All three gauges peg out as soon as I hook up the positive lead. I have changed all the grounds and just recently replaced the Alternator. It was the original Alt after 232K. I have read the instructions thoroughly, that I got from BMP Design and still can't get any of them to work. HELP! Anyhow, at least they look cool where they are at.
Do you have any links or pics to see this "ash tray pod" style of gauge holder?
As far as the help you need - all of the black wires will be going to a good ground. Find a good ground within the interior of the car, it has to be cleaned of any painted surface and make sure all of the wires are contacted evenly against the metal when screwing them down to secure them. As far as your positive leads - depending on which gauges you are running, you will want to find a good fuse in your fuse block to tap into for each functional gauge (ie: volts, lighting, etc). Again, make sure that each wire is secured properly and is making proper contact.
For instance, for the gauge lights - ground the ground (-) lead. There should also be a lead (+) that will come off the back of the gauge housing. Take this lead and tap it into the proper fuse for your interior lighting. If you have properly tapped into the correct fuse, the gauge lights will only illuminate when you turn on/off your parking lights, will also work when turning on/off all lights and they will also "dim" when using the dimming function.
Now for volts gauge, you need to tap the positive lead (+) into either a fuse or wire harness that will get power once the ignition will be turned on w/ engine running (KOER) and of course you ground the black (-) lead again.
Coolant temp, oil temp, oil pressure, trans temp, etc - all of these other gauges should come w/ specific instructions as for tapping the gauge leads into the proper senders for the engine.