Acura RSX Instrument Cluster mods for X19/K20

[Mark Olson]

I intend to use the instrument cluster from a 2005 Acura RSX in my X19/K20. I found a pinout for the cluster, and working through each wire I determined I can make it work for everything I want except for the Temperature Gauge and the Charge Light. I still need to test the Speedo and Tach, but I don't anticipate a problem as the Cluster has an input wire for each, and my Hybrid Racing conversion harness has the outputs from the K20.

With respect to the Temperature Gauge and the Charge Light, there are no separate input wires for them, so they must be fed by the MCU wire. As I understand it, the MCU (Multiplex Control Unit) sends out signals that are interpreted by the Cluster which then updates certain functions. To attempt replication of this data stream is beyond me, so I will need to address these two items in a more rudimentary fashion (read MacGyver lite).

Here is the Cluster powered up:

And here it is disassembled:

First I addressed the Charge Light.

The red circled item below is the led for the Charge Light. It sits at the top of a fairly deep socket:

I have a few switches that have led lights in the end of the switch. I cut one of these down to fit in the socket for the charge light and held it in place with a bit of Hondabond (RTV)

Here is one of the switches and my cut down piece:

When working with led's you have to remember to add a resistor to the positive wire to reduce the voltage so it won't burn out.

Here is my resistor in line:

With that in place I then turned to the Temperature Gauge issue.

First I bought one of these:

As you can see it has a ~90* sweep same as the OEM one.

Then I did this to it:

Here is the workings of the OEM gauge:

And with a bit of heat with a soldering iron where the red circles are below, it was out of there:

As well as being soldered in place, it's cover had some clips that went into the square holes. With a little round file I enlarged these holes slightly and was able to install the workings of the Equus gauge.

Here it is being test fit:

One more problem to address. The needle on these gauges presses onto the rotating pin. This pin on the OEM gauge extended farther out than the Equus gauge. The OEM pin was pressed through a plastic gear and was quite long. I removed the pin and shortened it, trimmed the gear so I just had the barrel left, and with a bit of JB Weld to help, used it to extend the pin to the correct dimension.

Here is the Equus workings with the extended pin:

And here it is in place (the red shrink tube contains the Charge Light wires):

The Equus gauge was also taller than the OEM, so I cut a hole for it to extend out the back. And another hole for the Charge Light wires.

Here it is assembled:

I sealed it up with a bit of Hondabond.

Here is the Instrument Cluster lit up, with all the lights activated:

I intend to use the round red light for my E Brake on light.

I tested the Temp Gauge with an electric kettle, a thermometer, and the sensor and it appears to work reasonably.

Here is the Temp Gauge at 190*:

I am happy with the result.

 

[lookforjoe]

Nice work, Mark!

Having gauges that start at 6 o'clock would take me some getting used to

 

[Rodger]

Very clever. So I assume you are doing a total custom dash as well?

 

[Ulix]

Cool project, nicely documented.
And I really like „Hondabond“!
I am wondering what „Fiatbond“ might be.

 

[Pete Whitstone]

Clever and creative mods, congratulations! I'm looking forward to seeing what the binnacle looks like.

 

[Mark Olson]

.... I assume you are doing a total custom dash as well?

Don't know if it will be totally custom, I intend to initially try to integrate this instrument cluster into the original dash but haven't looked very hard at the final design.

 

[Mark Olson]

I cut up my spare dash today, here is a rough in of what I am trying to accomplish:

Instrument cluster in the dash:

And with the dash in the car:

And a shot from the back:

As a side note - this dash is rusty, even rust on the metal surfaces where I scrapped off the foam. I expect the foam soaks up moisture which then corrodes the metal surface it is glued to.

 

[bjwhite]

Looks nice. Regarding the little red light for the handbrake, why not use the true location and icon? Also, maybe you can permanently illuminate the "maint req'd" light. hahaha.

 

[Mark Olson]

....... for the handbrake, why not use the true location and icon?

There is no dedicated wire for that light, and while I could wire up another led for that location, the round red light works just as well.

 

[homegrown32]

Wow I really like your solution!
I went with just letting it not work. And added 2 gauges down low by the shifter.
I do have a couple questions for you.
How do you take off the pointers from the stock gauges? When I tried I broke the parts.
How robust is the extension you JB welded on?
What would you do different if you were to start over again?
The other thing is I don't quite get where you're getting the charge light signal from? I have a similar setup is you. I have K-pro on the Honda computer. But I made my own harness similar to the one by hybrid racing. I used their wiring schematics I found online.
Again that looks really nice!

 

[Mark Olson]

The pointers pull off their pins. They are on tight. I managed to pull them off without breaking them, but it would work better to take a thin piece of metal, cut a slot the width of the protrusion on the back side of the pointer, and slide it between the cluster face and the pointer. When you pull up on that you would be pulling on the whole surface of the pointer instead of just a couple places. Breakage would be less likely. Another way is to unscrew the circuit board from the face and pull apart, keeping the face parallel to the circuit board. The needles should pop off. The face would provide full contact with the pointer.

The needle extension is reasonably robust, I have not tested it to the breaking point obviously. Both the gauge needle and the extension sit in the barrel so that helps the stiffness. I can put the pointer on and pull it off without it coming apart, and of course it is a fairly delicate piece anyway - doesn't need significant strength but must withstand vibration. If necessary it would be possible to make a longer barrel and with a couple tiny drill bits just create a press fit. Pretty fiddly stuff though.

If I were to start over I would probably do a little more investigation on how the stock temp gauge works. There are two coils that sit at 90* to each other, and the needle is attached to a round magnet that is positioned at the intersection of the end of these coils. Someone with more electrical knowledge than I have would probably know how to energize the coils in a way to make the needle move. I tried with a bit of trial and error but couldn't get it to budge.

With regard to the charge light signal, the simple answer is "I don't know for sure yet". Although I understand there may be a wire I could tee into from the alternator that could provide this signal. If that doesn't work, and another simple solution isn't available then I would use an Arduino board. I have played a wee bit with one of these, and it would be a relatively simple thing to program the board to turn on the light if the input voltage falls outside of a specific range. I would then just get the input voltage from the battery, and use a range of 12.5 volts to 16 volts or something similar.

I look forward to seeing your progress fitting this into the rest of the instrument panel.