Triple Gauge Swap, 2021!

Act 3: Mounting the Gauges

Previously in part 2 I went over the setup of the necessary probes and fittings for the oil temperature and oil pressure (water temperature will come later). This post will be about all of the fun/drama (there isn’t always a difference when it comes to cars) that you have to go through to mount these gauges.

I am going to break down part 3 of this process into several steps:

1. Hardware info
2. OEM “gauge” removal
3. Mounting solution for new gauges
4. Mounting the control unit
5. Video time!

Hardware Info

To recap, I’m using the Defi Advance gauge system. There is a control unit that will be mounted in the dash. All of the sensors/probes plug directly into this unit. The gauges also plug into this unit. The gauges can then be daisy chained off one another, so you only have to run a single wire from the control unit to the gauge cluster. There are different gauge styles that
can be used. I went with the BF series for two reasons:

1. They “black out” and you can’t see anything when they are not powered on.
2. They look VERY close to the stock gauges. I don’t want blue or white or purple gauges all over the cabin to blind me. You can probably already see how stock these look in some of the banner images for this site. If not, here is a comparison between off and on. If you look closely, you can see that I have the gauge hats in the wrong locations
   

Those are the gauges. So what about the control unit? The control unit is a small box that will go inside the dash behind the stereo. It has connectors on the back for several different types of probes. So far, I only have three: oil temperature, oil pressure, and water temperature. It also has a connection for a fancy remote that adds many features that you will not get if you go with a more traditional gauge setup.

OEM “Gauge” Removal

Before removing the gauges, you must obviously remove the center trim (in my case this is the cubby assembly including the vents) and the stereo/HVAC controls. This will differ depending on which model you have. I have the base model, so I don’t have the Bose stereo or the nav screen with integrated HVAC controls. This will all need to be removed. I may make a post about that later, but for now, just basically start removing screws until you can pull plastic bezels off! There will be several harness connector clips that you will have to remove in the process (ignition button, air bag indicator light, etc…). The harness wires are not long at all, and will be annoying to remove. Now, before we move on, note how the word gauge is in quotes in the heading? There’s a reason for that, and it will be clear shortly. The first step in the process is removing the three hats and hat brackets that cover each one of the gauges. Before going any further, please understand that THE GAUGE HATS AND HAT BRACKETS ARE UNIQUE. Don’t make the same mistake I did, and not pay attention to which position each hat and hat bracket came from. Mark the hats and hat brackets. Now. Below are some images of the hats and their brackets, and how they fit together

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You should be able to CAREFULLY pry up on the front lip of the hat. It may or may not come out as a single unit with both the hat and the hat bracket together. People on the forums say they come out as a unit. Mine did not. In any case, it doesn’t matter anyway because we will have to take a dremel to the hat brackets.

Do you remember above where I put the word gauge in quotes? This is why: The displays in the Nissan are not traditional gauges that one would think of in this regard. What appear to be gauges is a single piece of plastic, with a single circuit board inside, and three faces; two of which appear to be gauges. See the images below. Some were stolen from ebay auctions because I can’t find mine at the moment. In the last image, I tried to show how the clip in the gauge hat bracket mounts into the gauge body itself.

Now that the hats are removed from the gauge arm assembly shown above, we need to remove the assembly from the dash. This is where the fun starts. There is a small tab on the bottom of the gauge arm assembly. This tab fits into a small metal bracket, which is what attaches the gauge arm assembly to the inside underneath the dash. Remove, but DO NOT LOSE this metal bracket. You will need it again later for mounting the arm for the aftermarket gauges. Unfortunately I didn’t get any pictures of this mounted, but it will be clear once you see it through the gaping hole that once housed your cubby (or nav screen). I do, however, have a picture of the bracket, shown below. Again, do not lose this. People have asked me, and I have not found anywhere that this can be purchased. I may try to model it and 3d print it in nylon or ABS at some point, but for now, hold onto it.

After you remove that bracket, you will see that there is no way to remove the gauge arm assembly from any of the three holes. You will try. You will reposition it. You will plead with it. You will swear at it. You will eventually come to the conclusion that you have two choices: You can either destroy the gauge arm assembly and remove it in pieces, or you can remove the ENTIRE dash. This includes removing things like the steering wheel and air bags. I quickly chose to shred the gauge arm assembly. Replacements can be had for about $60 on ebay, so don’t feel too bad about destroying it. My weapon of choice: channel locks from Harbor Freight. The following image is probably my favorite one from the entire install: It shows the disemboweled gauge arm assembly all over my passenger side floor. This was surprisingly therapeutic; take it slow and enjoy it!

I should mention that you want to be careful when destroying the gauge arm assembly. One of the reasons that I didn’t want to remove the entire dash is because every time I’ve done this in the past, no matter the vehicle, I always get rattling sounds from behind the dash (something you might expect if you broke off a plastic retainer clip or dropped a screw back there). It is VERY easy to get carried away when removing the gauge arm assembly and allow pieces to fall through the cracks. This will be a major headache. Consider yourself warned. After you have fun obliterating the gauge arm assembly, your dash will look something this, with these ominous caverns lit from within.

Mounting Solution for New Gauges

Once you get done removing the gauge arm assembly using whichever method you chose, you will surely be wondering how you are going to mount your aftermarket gauge cans in those holes. It doesn’t look like there is any way to secure them. Well, have no fear! There is a member of the 370z forums who makes an awesome bracket to use to mount these gauges. I was scared to attempt this until I stumbled on his forum post. He sells them on the forums for a very reasonable price. his forum name is “scope22” and you can find his thread on the 370z forums here: http://www.the370z.com/exterior-interior/128620-bracket-aftermarket-gauges.html This would not have been possible for me without having his bracket. Do not attempt this without it; you’ll only give yourself a headache! The best way to get in contact with him is his IG handle: lotusworks_370z. He has a lot of cool products aside from the gauge mounting arm. After you order the bracket, he will send you the mounting arm and three baskets; one for each gauge, which will attach to the arm (this is what is shown in the first pic on this blog post). The gauges each sit in a basket, and each basket is attached to the arm. Do you remember the metal clip on the back of the gauge hat bracket? It fits in the square hole on the back of the gauge baskets below.

The idea here is that the gauge hat will sit on top of the gauge hat bracket as it already does. The gauge hat bracket will now sit on top of these gauge baskets. This sounds simple enough, but unfortunately things are never as easy as they seem to be. In order for the gauge hat brackets to sit on top of actual gauges, they need to be modified. Basically, this in involves widening the midsection of the gauge hat brackets until they can fit around whatever aftermarket gauges you chose to go with. Because I am using aftermarket 60mm Defi gauges, this is how far I had to open mine up. Depending on your choice of gauges, you may need to remove more or less material than this. Make sure to go slow and test fit them often, so you don’t remove any more material than necessary.

Once these are assembled and test fit together (see the first image here), you’re ready to install them. You need to disassemble them and they must be installed in pieces. If you did not remove the dash first then you will need to snake the arm bracket in through the gauge holes. There is only one way that this can go in. You should refer to the installation video that scope22 posted in the forum. He shows exactly how to maneuver it in. Don’t get impatient like I did and break it because I wasn’t smart enough to watch the video. You can either check out his post in the forums (link above), or just watch his youtube video here

Mounting The Control Unit

After opening up the dash you surely noticed all of the space back there. This is another area that will vary depending on which Z you have. My humble base model has the standard 2009-edition stereo. Once you get behind the dash, you will see that there is a bracket that holds both the stereo and a nondescript white box. For the curious out there, the box is officially called the “TEL adapter” by the factory service manual. Interestingly enough, you need this box for more than just telephone functionality. For some reason, the HVAC will not work if this unit is not connected. I chose to use some heavy-duty Velcro to mount the Defi control unit to the TEL adapter. It fits in there nice and snug, and doesn’t go anywhere.

Now that the location has been decided, we have to figure out how to wire it up and feed it a steady stream of electrons (that’s not really how it works). It’s easy enough to tap one of the many harnesses for constant and switched +12V signals (check out the AV section of the FSM for pinouts of all connectors). I am eventually going to need power for several accessories behind the dash and I didn’t want to tap power from different harnesses for each accessory. I ended up buying a cheap fuse distribution box from amazon (link here) and ran a dedicated line from it to the battery, with a waterproof crimp connector. There is a lot of room behind the dash to the left of the stereo, and this tucks in there perfectly, with plenty of room to spare. This takes care of constant power and ground. For the 12V switched signal I did end up tapping one of the harnesses. I don’t remember at the moment, but I believe that I tapped the TEL adapter unit for this. Once again, check out the AV section of the FSM for the pinout of its plug.

To power the fuse block, I ran a line of 12 gauge silicon-jacketed wire from the battery into the cabin. There is a large bundle of wires going through a rubber boot from the engine bay into the cabin, I slipped this wire in through there next to the large bundle, and pulled it through in the passenger-side footwell. Below you can see the battery connection and where I pulled it through from the engine bay. You can also see the three wires for the gauge probes coming through the same rubber boot. Remember to ALWAYS fuse your lines from the battery, as close to the battery terminal as you can get. There is NO excuse not to do this!

Video Time!

Here are the opening and closing “ceremonies” (that is what the Defi manual calls the animations). There are two opening and closing options. The one I picked is the more annoying and elaborate version. They are selected by DIP switches on the side of the control unit. For some reason I am missing the gauge hat for the oil pressure gauge, but I don’t remember why.

As always, I welcome all feedback!