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© 1999 Brian F. Schreurs
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Of course, oil gauges should be bouncing all over the place. The pressure is different depending on engine temperature, engine speed, and amount of oil present. You'd never know it by watching the stock gauge.

So it's AutoMeter to the rescue. We bought their electric oil pressure gauge (#2634) which we're mounting in a Mustangs Unlimited dual-gauge A-pillar pod (#77L409). The oft-visiting 1995 Mustang GT is the patient. By the way, in the course of this operation we also bought a replacement oil sender unit (Niehoff #FF135E), two anodized pipe-to-AN fittings (Russell #6041), a braided steel nitrous hose (NOS #15020), and various bits from Home Depot Racer's Supply. We might not be the only ones (hint-hint).

Remove the old oil pressure sender.

Okay, that's not very nice of us. By now you've probably already noticed that the usual manuals either fail to address the oil pressure sender at all (thanks Haynes), or have a handy diagram of the wrong one (thanks Chilton).

Looking for this? The oil sender with the wiring removed.

So Where's The Sender? It's not so hard to find really. From the front of the car, look down the front of the engine, betwen the water pump and power steering pump. You'll see the oil filter down there. Just above the oil filter there's an indentation in the block. At the front of that indentation is a bracket with an electrical harness of some kind on it. Behind that bracket is a cream-colored cylindrical thing with a wire attached. That's the oil pressure sender.

Hand tight?? Hahahaha. You wish.

Detach the sender's lead. Now take the wire bracket off. The top nut is 1/2". This will free the wires, which you can pull out of the way. The stud will still interfere, so use a 5/8" wrench on what appears to be a second nut. It's actually part of the stud so you'll be able to completely back it out.

Now you have clear, if not easy, access to the sender. The sender itself is removed with a special Ford sender socket. Ohhh... don't have one? Neither do we. Go get yourself a nice 1-1/16" socket that you're likely to never use again. Get a 6-point (grabs the flats rather than the grooves) and don't bother getting a deep one (no clearance). What? the standard-depth won't fit? You're right -- get out the hacksaw and cut the post off the top of the sender. Now it'll fit.

Of course, now the original sender is unusable. That's why we told you to buy a spare if you're setting up a dual-sender system like ours.

The old sender wire won't reach the sender in its new location. Splice in an extra length of wire.

This is what the dual-sender bracket looks like.

Now for the new and exciting dual-sender mounting system. The goal is to hook up two senders where there used to only be one -- one that you could barely even get to. Starting from the engine block, here's how to build it (be sure to use thread sealer on all connections):

There's no room for two senders at the block. But they can be relocated. Thread a 1/4" to 1/8" fitting into the block. Thread the Russell 1/8" to -3AN adapter onto the NOS braided line, then into the fitting. [Note: if you can find a 1/4" to -3AN adapter, the 1/4" to 1/8" fitting isn't needed.] Thread a -3AN to 1/8" fitting onto the other end of the NOS braided line. Now the sender port has been relocated to the end of the braided line, so we can put the senders anywhere that line will reach.

Your work with the block is done. Reattach the wiring bracket. It's being used as a ground already, so it's a good place to ground the new oil gauge (it's important to ground the gauge near the sender; if the ground resistance differs greatly from the sender resistance, the gauge could read funny).

Now we can build the dual-sender system. Start with a 1/8" T-fitting. Attach two 90-degree elbows, one on each side of the T, so that the open end points up (opposite of the T-bottom). On one elbow, thread on the NEW sender. On the other elbow, attach a 1/8" to 1/4" fitting, then thread on the replacement STOCK sender. Now you have a dual-sender system.

This is what the dual-sender system looks like.

To mount this thing, you need to build a custom bracket. Start with one of those pre-drilled T- bars from Home Depot Racer's Supply. The holes aren't big enough, so drill out the first hole on the T-bottom until the sender system's base will fit through it. It may require a bit of fine-tuning with a file. Now look at the water pump. Remove the upper driver-side bolt; it's a 1/2" head and is very long. That's where the bracket will ultimately be mounted, so use that bolt as a guide to drill out the far-left hole on the T.

With those two holes enlarged, it's time to bend the bracket into shape. The first bend is just before the large hole on the T-bottom. Bend it 90 degrees forward. The best way to do this is to grab the bending point with a large adjustable wrench, then grab the bar lengthwise with needlenose Vise Grips, and bend. With that bend in place, move down the length of the bar to just after the enlarged hole and bend 90 degrees up.

Nothing need be done with the unused part of the T. It will actually handily brace against the power steering pump during reassembly, but if you'd rather not have it there you can cut it off without worry. Of course, if you're going to cut it off anyway, you should have started with an L- bar instead of a T-bar.

Final assembly: push the water pump bolt through its hole and set the sender system into its hole. The sender system should be positioned so that the new sender is nearest the water pump. Thread this bracket/sender combination onto the end of the NOS braided line. Make sure it's good and tight. Now start threading the water pump bolt back where it belongs.

It's a big fat nuisance for a while, but eventually that extra part of the T-bar will catch on the power steering pump and installation will go much faster.

Installed: A tight fit, but nevertheless a fit.

With everything in place, and the senders clear of the belts (they should be), wire them up. Reattach the stock wire to the stock sender, and put a connector on the end of the new wire to sandwich between the sender and its bolt. Be careful here! There's what appears to be a thumbscrew underneath the top nut on the sender. If you move it, you'll break it! Just remove the nut. You may have to hold the lower portion with pliers to keep it from moving.

The sender and ground wires can follow the existing harness around the accessories, then up the inner fender to the master cylinder, and through a firewall grommet located on the passenger-side of the master cylinder.

Had we been thinking, we would have poked a hole in the center of the grommet and run the wires through that. We weren't thinking, however, so we just took the grommet out and ran the wires through the big gaping hole. When we went to replace the grommet we had to cut a notch in it for the wires. Oh well.

If you're attaching more than one gauge, stop here and wire the other sender as necessary. We also hooked up a transmission temperature gauge.

The rest of the work is done inside the car. Note that if you're installing more than one gauge, all these instructions apply to all gauge wiring.

If you haven't already disconnected the battery, do it now! You'll be working around the air bag and they don't like being disturbed.

Remove the plastic trim covering the A-pillar on the driver-side. It's easy; just pull hard.

Take the dashboard apart. To get the front fascia off, you must first remove the headlight knob. Pull the knob to its full-open position and look for a slit near the base. Supposedly there's some sort of clip in there that you just loosen with a pick or punch, but we dunno. We just fiddled with it for about a half hour till it fell off. It'd probably be easier to just buy a new one and break the old one off.

Whack dem posts off with a hacksaw.

With the headlight knob out of the way, it's possible to pull the fascia off. It's held in place by two Torx bolts, size T-15. They are located along the upper edge. With those removed, gently pry the fascia off.

This will give you access to run wires from the grommet to the A-pillar. Instead of trying to shove the wires up through the dash (you can't push a rope), use a spare length of wire as a guide line. Start at the A-pillar and route it down through the dash, to where the sender wires are waiting. Tape the sender wires to the guide wire and pull them back up. It may take more than one trip since you'll likely have a fairly large wad of wiring to cram through some fairly small openings.

Here's a quick inventory of the wires you'll be running:

• sender wire [two if running two gauges]
• ground wire [two if running two gauges]
• gauge power [two gauges can be spliced together in the A-pillar, for just one wire]
• illumination power [two gauges can be spliced together in the A-pillar]
• illumination ground [two gauges can be spliced together in the A-pillar]

The wiring is only confusing if you didn't carefully label them.

So if you're just installing one gauge, there will be five wires. If you're installing two gauges, there will be seven wires (assuming you splice together wires where you can).

You're already routing the sender and ground wires up. You'll also have to route the power and illumination wires back down. Before you connect the wires, you should position the gauge in the A-pillar pod.

Basically, the gauge has two mounting studs that get in the way of everything. Use a hacksaw to cut them off. Now the gauge should just press into the pod without any trouble.

With the gauge in the pod, continue the wiring job.

The sender wire and ground wire should already be attached on the chassis end. On the gauge end, they attach to the gauge posts as labeled. If you lose the label, it's also stamped into the housing. In fact, all the wire posts are carefully marked on the gauge end. Just follow the diagram on the back of the gauge, and we'll help with the chassis side.

The gauge power wire needs to get ACC-on power (i.e., it's off when the car is off but it's on with the key in the ACC position). We already have ACC-on power because of our Foglight Switch but you'll find plenty of wires to choose from under the dash. Just use a multimeter to find a wire that meets the criteria.

Now, the gauge needs to light up when the parking lights are on. The headlight switch is right there, so it's easy enough to tap into that and run the gauge in series with the parking lights.

Wrong wrong wrong wrong wrong!!!

Ford has some bizarre setup in the headlight switch, wherein it receives power when it's off and no power when it's on. If you tap into this, your gauge lights will work exactly opposite what you want. Not that we did it or anything. Not us. Nope. We heard about it somewhere. Yeah.

The illumination wires need to tap into power and ground for your parking lights. You can look around for the harness under the dash if you want. It's gotta be there somewhere. We cut out the middleman and went straight to where we knew the circuit would be the way we wanted: we spliced into the wiring harness at the front-driver parking light.

Patch into the parking lights to get the gauge lights to work properly.

If you want to do it our way, lift the plastic flap covering the driver-side headlight. From there you'll be able to access the bolt (sorry, we forgot to write down the size) that holds the side light in place. Then just disconnect the wiring harness from the housing. As usual with these darn plastic clips, they're brittle and likely to break. So be careful.

Use a blade to cut away some of the plastic insulation, then use a multimeter to determine which power wire is the parking lights (you don't want your gauges to blink with the turn signal do you?). Run the illumination wires out to the harness (we just followed the route we already used for the Fan Switch) and splice the power wire into the harness. Then put the insulation back on and tape everything up.

The ground wire can ground on one of the green screws just next to the battery, on the radiator support. Easy. Then put the marker light back together.

Trying to jam all those wires under the pod can be tricky, but they'll fit.

The gauge should be all wired up now. All that's left is to mount the pod to the A-pillar.

Put the factory A-pillar trim panel back in place. We're using self-tapping screws; the tape is worthless. Wedge the pod as far down on the A-pillar as it will go. It should sit there on its own, although it might pull away a little. No matter. Check for fit and to make sure all the wires are tucked away.

The oil pressure gauge is on the top.

Home Depot sells plastic caps to hide the screws. These are cool, but hard to open once closed. To fix this, use a knife to cut a small slit in the side of the cap. That way you can jam a pick in there to pop it open when it comes time to service the gauge.

Slip the screws into these caps, then get in the car and hold the gauge pod in position. Line them up, one on each side of the pod's curve, and just push. They'll screw into the aftermarket and stock trim panels with a little effort.

Close the caps to hide the screws.

Put your dashboard back together! It should all go okay, without surprises, except that the headlight knob will be as hard to get on as it was to get off.

Hook up the battery and go! You're done!

Man oh man that was a lot of work. But the new gauge looks really, really cool. With this much engineering involved, AutoMeter is a little misleading about the ease of installation. That's okay though, most people probably pay a pro to do something like this. For us it's another notch in the tool chest.