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After recently completing installation of my accessory gauges, I feel learned a few crafty tricks, that didn't seem to be nicely documented anywhere, so I wanted to jot them down for the next person.
My gauges were in the upper portion of the lower cubby. Voltage, Oil Pressure, Outside air temperature.
Before installation, I highly recommend assembling, AND SECURING the wiring for the gauges out on a bench. Crimp on connectors, zip tie everything together, and leave LONG lengths of wire coming from gauge pack, to run through the car.
DASH LIGHTS - Tip #1. Each gauge needs 12V, GND and the signal to the gauge, as well as 12V and GND from the dash lights for backlighting. Tie the GND side of the backlighting bulbs, to GND for the gauges; no need for 2 ground wires. For the dash lights and GND, remove the radio and cage. Removing the exposes a dash light that plugs into the HOT/COLD selector knob area to backlight it. This light, along with many others are faded by the dash rheostat, and connect to the bulb using 2 female spade connectors. The dash light has male spade connectors. Coming from the back of your accessory gauge cluster, run 2 wires up to the radio area; 12V for the backlighting, and GND. Take a male crimp connector, and attach the wire going down to the gauge, AND another section of wire (2-3" long) onto that male connector. Crimp. Do the same on the GND wire. On the 2-3" long end you left, crimp a FEMALE spade connector on. Attach the OEM wiring to the bulb, to your new MALE crimp connector, and your new FEMALE crimp connector to the OEM bulb. (the GND wire in the OEM harness is black, and doesn't have any plastic insulator over the connector. The 12V does. Keep them straight).
At this point, you have 12V to backlight the gauges, driven off the rheostat, and GND, down to your accessory gauges, and you didn't need to cut a thing. You simply unplugged the light from the dash, plugged in your harness in jumper-formation, and reinstalled. Turn on parking lights to verify lights work, and dim with rheostat operation.
PRO-TIP: The OEM bulbs usually have a green silicone cap over them to green the look of the backlight; not yellow. USE A GREEN SHARPIE TO COLOR THE BULB. Works excellent and provides a nice green backlight.
GETTING THE WIRES OUT OF THE CAR - There are several grommets you can use in the firewall. I went for one JUST below the very most rearward portion of the underhood fuse panel. Its almost impossible to see, but you can feel it from the outside, and can BARELY feel it by squeezing your hand up behind the knee bolster. I ran wires for switched 12V, oil pressure, and outside air temp through this hole. I removed the grommet, cut an X in it with razor blade, fed the wires through the grommet, then reinstalled the grommet to seal it back up. At this point, all of my external wires are in the no-mans-land area behind the underhood fuse panel.
VOLT GAUGE - You have GND taken care of when you jumpered the gauge GND to backlighting GND, and connected it to the bulb behind the HOT/COLD selector switch. All you need is switched 12V (which is also fed to the other 2 gauges, and should be taken care of when assembling everything on the bench before installation in the car). I got this from the fuse panel under the hood on the drivers side; from the not-present daytime running light relay (US-spec). Using a meter, bug light, etc probe the pins of the relay with the key on and off to find switched 12V. I believe it was the most rearward; a red/white wire. Using a SMALL flathead screwdriver, push it down in front of where the connector is in the fuse panel, while pulling downward on the white/red wire, and it will pull out of the bottom of the fuse panel. NOT NECESSARY but I wanted a stealth look. All you NEED to do is connect your 12V to the volt meter, to this wire somehow. I crimped a male spade connector on my wire, and connected it to the white/red switched 12V, heat-shrunk it together and buried it under the fuse panel. If I ever want daytime running lights, I simply unplug my gauge, push the connector back into the fuse panel, and install the relay. At this point, all gauges should power up with the key on, and volts should read accurately. Outside temp and oil pressure should not.
OIL PRESSURE - The OEM oil pressure sending unit threads into the oil filter housing, and has 1 male spade connector. The threads are M14x1.5. The oil pressure sending unit I happened to have used 1/8" pipe thread (NPT). I needed to purchase an adapter - Auto Meter part number 2267. This adapter is brass, and soft. PRO-TIP: Install the gauge into the adapter with it held in a vise, on the benchtop, THEN install the whole apparatus into the oil filter housing. It is EXTREMELY easy to cross-thread the sending unit into the adapter, and being soft brass, you can hardly feel it binding. Don't mess it up. On my car, when I went to install the assembly, it hit one of the oil cooler lines, and I was forced to loosen both (16mm wrench), rotate them upward, and retighten to gain clearance. Once installed, put the OEM female spade connector on one of the prongs, and the 1 lone wire from your oil pressure gauge, to the other prong. I ran the wire through the grommet, under the fuse panel, and through a small opening in the inner fender RIGHT beside the fuse panel. The wire comes out near the ABS brake lines; fish it through and connect. When you start the car, look at your gauge and warning light. If the gauge is pegged, and the warning light is dim, you have the wiring backward on the sending unit; swap them. The correct ohms on the sending unit is 10-180, in case you need to purchase a new sending unit.
OUTSIDE AIR TEMP - The one wire for the sensor is again down by the fuse panel. I ran it along the inner fender wiring harness toward the drivers side headlight, and fed through an opening in the inner fender that dumps in JUST in front of the intercooler. From there, I ran down under the front bumper and installed the sensor in a grounded location. It came with an L-bracket that the sensor screwed into, then that bracket mounted. If the bracket was not grounded, the sensor does not work. You can't zip tie, or leave it hanging. It HAS to be attached to a grounded location, or have a separate ground wire attached, then grounded elsewhere.
posted by 129.33....
, Mon, 30 Apr 2012 19:49:38, Fri, 27 Apr 2012 11:22:38
, Fri, 27 Apr 2012 14:26:55
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