Fasten a round eyelet to the end of the ground wire and bolt it to a metal surface that does not have any paint on it. Splice the power wire for the gauge light into the existing gauge light wiring harness.
How to Wire an Oil Pressure Gauge
You can use an inline splicer or simply cut into the wires and tape the gauge's power wire to a wire that runs to the existing gauges. Run the oil line through the firewall and into the engine bay after you have mounted the gauge. Locate an existing hole that wires go through and use that for the oil line. If you cannot locate a hole, drill a small hole. Insert a rubber grommet in the hole to protect the oil line. Locate a suitable threaded oil fitting in the engine's block. If your car uses a factory oil pressure gauge, use that fitting to install the new oil line.
If your car has an oil pressure warning light, this will also be installed in the block, but it will likely be only a wire that runs to a sensor. Install the threaded fitting that came with the oil pressure gauge on the other end of the oil line. Wind Teflon tape around the threads on the fitting to prevent leaks.
Thread the fitting into the block. The gauge kit will likely come with several different fittings that have different threads to fit a variety of makes.
Start the engine to ensure the oil gauge is correctly reading the engine's oil pressure. The necessary hardware can be purchased from an auto parts dealer, if not included with the oil pressure gauge.
- Fitting an oil pressure gauge.
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Choose a suitable location to mount the oil pressure gauge; mount the gauge so it is easily viewed while driving. Common mounting locations for aftermarket oil pressure gauges include under the dash, on top of the dash, or set into the dashboard. Mount the gauge panel to the dash with a screwdriver and screws provided in the kit; set the gauge aside. This makes it easier to connect the wires. Remove the oil drain plug from the oil pan with a wrench and drain the old oil into a oil catch pan.
This is an opportune time to change the oil filter as well. Remove the old oil pressure sending unit with a ratchet and socket; the oil pressure sending unit is shaped like a cylinder and is usually located near the oil filter.
Refer to the new oil pressure sending unit in the oil pressure gauge kit to help you identify the part. Connect the signal wire to the sending unit and run it through a grommet in the firewall in close proximity to the gauge.
How to Install an Oil Pressure Gauge | It Still Runs
Run the wire through the gauge panel hole, or the pre-drilled hole in the dashboard, allowing extra wire for easy connecting. Connect the signal wire to the post on the back of the gauge.
The gauge posts are marked for correct wire installation. Run a power supply wire from a switched volt power supply, such as the cigarette lighter, dome light, radio, or fuel pump, to the power post on the gauge.