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Discussion Starter · #1 ·
I hope this will be interesting and informative. As an electrical engineer, and somebody who likes taking stuff apart, I've always enjoyed looking at teardown pictures of electronics like cell phones, game consoles, and such. I managed to pick up a Cruze instrument cluster from a wrecked vehicle on the cheap, and was thinking of trying to turn it into a clock/thermometer/something, so I decided to take some pictures while disassembling it.

You look at your Cruze's instrument cluster all the time. Whether it's a quick glance at the speedometer when you see a police car up ahead, or a snapshot of your manual transmission Eco's DIC to brag about, this part of your car is probably second only to the window glass on the list of parts you find yourself looking at often. But what's inside it? Maybe you've had the displeasure of replacing a burned out idiot light or gauge backlight on a previous car, and wonder how difficult that would be on your Cruze. Maybe you've modified a cluster before, changing the backlight colors, converting to LEDs, replacing gauge faces, etc. and wonder about doing that kind of thing.


So, let's get started. Here, we have a familiar sight - the front of the cluster.
Gauge Speedometer Auto part Vehicle Car


Let's take a look at the bottom. Here we can see the strip of vinyl that goes between the cluster and the steering column. Looking at this, it's just hot-melted to the bottom of the plastic cluster. Try to avoid pulling on this when working on your car, it could pull off rather easily (one corner is already coming loose on my junkyard cluster here, circled in red).


OK, let's take a look at the back. So far, we have one connector, a part number sticker, and a large GM logo. Interestingly there's no manufacturer's name or country of origin listed. Strangely absent are any of those little plastic holders for light bulbs. Maybe they're hiding behind the translucent plastic? This is where our disassembly will begin. To get started, remove the 5 Phillips screws circled in red. After these are out, you can pull gently on the part of the translucent plastic that sticks out above the blue connector on the top left. Some clips should release, but there are still a few more, I've circled those in green. You should be able to carefully pry the translucent plastic out of the white plastic with a plastic pry tool like the ones commonly used for cell phone repair, or a small flat blade screwdriver (but a screwdriver might mar the plastic.)
Vehicle Car


Now with the plastic cover out of the way, we see one large PCB. Unlike many older GM clusters, this is a rigid green fiberglass PCB, not one of those flexible plastic ones that liked to deform and cause fun things like the Check Engine light coming on when you hit the right turn signal or the backlight for one of the gauges only working on particularly warm days or other such insanity. There are 4 large black things visible, these are the motors that move the analog needles but that's about it. Still no sign of those light bulbs, so I guess we'll have to delve a bit deeper. Can we just pull the PCB out? Unfortunately, no. Trying that, we can see that it's trying to pull the gauge needles out through the dial faces - probably not a good idea.


To progress further, we need to remove the white piece of plastic that the PCB is stuck to from the black housing. This is held in by several clips molded into the plastic housing. We can work our way around, carefully bending back the black plastic clips and pulling the white plastic out.
Personal protective equipment Helmet Vehicle
Gun Technology Finger Camera accessory


And now we have a large empty plastic bezel. This is pretty unexciting, except to note that the trim rings around the fuel and temperature gauges are molded into the plastic housing itself. I didn't go further disassembling this, there are more snap clips and some tape, but separating the two black plastic pieces should allow the clear lens to be removed for cleaning/replacement.
Electronics Auto part Boombox Eyewear Games


Now for the first particularly interesting discovery: The gauge faces are actually all one big piece of transparent plastic with the legends painted on.
Speedometer Gauge Tachometer Auto part Measuring instrument


More to come soon - I'm still editing my photographs.
 

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Discussion Starter · #2 ·
WARNING: Disassembly beyond this point could easily break something. This is a junkyard cluster that I picked up cheaply for a project, not the actual cluster out of the car I drive to work on a daily basis.

To get that plastic face off, or get a look at the front of that PCB we'll need to remove the gauge needles. I spent a while staring at the gauge motors and needles to see if there was some magical release thing and couldn't find anything. The gauge needles are on pretty tight, but will come off if you pull firmly. The needles themselves appear to be constructed of 3 pieces of plastic - a clear plastic 'stem' that goes onto the shaft of the gauge motor, the clear plastic needle with red paint, and the black plastic trim ring. These are all held together by melted down heat stakes on the black plastic trim. WARNING: I don't know how fragile the motors are - after removing and replacing the needles they still seemed to rotate, but I don't have a way to hook this up to a car and make sure it still works since rumor has it that clusters are VIN-locked and installing a non-matching one can leave you with a car that thinks you're trying to steal it and thus won't start.
Speedometer Gauge Technology Electronics Electronic instrument


Now that the needles are off, the PCB will simply fall out, giving us a first look at some more interesting stuff than the back of the board. I apologize for the large size of this picture (but on the other hand if you'd like it even larger, I have a full-size version that shows the detail a bit better). Here we see the DIC LCD, with a flex ribbon cable connecting to a socket on the PCB, a few chips (I'll list part numbers later), and a lot of large surface mount LEDs. Yup, not a single incandescent bulb anywhere. All of the backlights, idiot lights, etc. are permanently mounted LEDs that should in theory substantially exceed the lifetime of the car itself. As a point of information, I collect old calculators, and own a few from the 1970s with red LED displays that still work perfectly, so 40+ years of life for an LED is possible.
Motherboard Electronics Technology Electronic component Computer component
 

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Resident Derp
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Too bad they're LEDs, I was hoping for something easier to solder to change the color of the back lighting.

Awesome write up though! Really informative, this is pure awesome.
 

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Discussion Starter · #4 ·
Here's a closer picture of one corner of the board. The small white rectangles with the round lenses on them are LEDs for the various indicators and backlighting. The blue goo you see around the computer chips on the board is conformal coating, which serves a few different purposes: It's commonly used on automotive PCBs to help protect them from the elements (old GM PCBs, especially things that went outside the car like engine controllers, ABS brake modules, etc. typically had the entire board dipped), and also for components with fragile pins to help keep pins from popping loose due to vibration. Another more nefarious use of conformal coating can be to make it difficult to modify/repair the PCB (although a more effective method of doing that is to put hard epoxy that can't be removed without the use of nasty solvents that would be likely to eat the board over the interesting components)

Motherboard Electronic component Computer hardware Electronic engineering Electronics


Now we can remove the DIC LCD panel. There's probably not too much of interest under here, but maybe we can get some info about the LCD like a manufacturer's name or part number that could help us reuse it for other projects. Also, if you ever managed to break the LCD in your car somehow, the LCD doesn't seem to have any kind of computer chips on it, so I suspect replacing the LCD could be done without having to reprogram the cluster. To start, we'll want to unplug the ribbon cable. To do this, we can just pry up the black plastic latch that holds the cable in the connector using a plastic pry tool or regular screwdriver (once again be careful if you're using a screwdriver). Once the clip is up, just carefully pull the ribbon cable out of the connector.
Computer hardware Electronics Electronic engineering Technology Electronic device


To remove the LCD and its plastic carrier from the PCB, we need to release 4 white plastic clips on the back of the PCB. Your fingers will work just fine for this, the plastic is pretty flexible.
Metal


Now, we can see what's underneath that LCD. Not much in the way of components - just 4 more surface-mount LEDs, these are the backlights for the DIC. However, we do find a couple of interesting markings - a part number, a logo, and a manufacturer's name - Yazaki (Yazaki North America - The Leader in Delivery of Robust Power and Data Networks). If you look at the pieces of plastic we had to remove to get to this board, you'll find the Yazaki logo somewhere on all of them as well - I missed it at first because of the large GM logo. Unfortunately I don't think "This Japanese automotive component supplier manufactures the instrument cluster for the Chevrolet Cruze" is going to be a Final Jeopardy question anytime soon, but it is kind of interesting to see GM using a Japanese supplier for their clusters as opposed to a US vendor like Johnson Controls or a German one such as VDO.
Electronic engineering Electronics Electronic component Motherboard Electrical network


Here's a brief rundown of chips I noticed on the PCB:

The large square chip (TQFP package, I think) is marked "D70F3426AGJIAI". This appears to be a Renesas (formerly NEC) uPDF70F3426 microcontroller, probably the main "brains" of the cluster. I was hoping that the large number of pins on the connector for the cluster would mean there wasn't much in the way of intelligence inside it, which would make repurposing it for my project a lot easier. Here's a sales brochure with a few details about the micro (http://www2.renesas.eu/_pdf/U17736EE1V0PF00.PDF), reading this we can see that it contains 2048 KB (2 megabytes) of Flash ROM, so it could in theory be reprogrammed. Some internet searching will find the datasheet for the chip, I didn't post it here because it's almost 1000 pages.

The small 8 pin chip directly above it is marked "L080" - probably a 25L080 8K SPI EEPROM. If I had to guess, I'd say this chip probably stores data the cluster wants to keep track of (maybe the mileage, car's VIN, etc.) since the microcontroller may not be able to write to its own program flash, and if it could, there's a chance that power could be lost during a write, corrupting the programming.

There are several Texas Instruments ULQ2004AT 8x Darlington transistor pair chips. I haven't followed traces yet, but these are probably driver chips for the LEDs (since cluster indicator LEDs would have to be pretty bright to be visible with the sun hitting the cluster, and the output pins on the microcontroller probably can't drive enough current to light them).

I hope you found this interesting. If you did, and there's more stuff you'd like to see, just ask and I'll see if I can take pictures of it. If I ever manage to reverse-engineer the thing to the point of being able to reprogram it for my clock/thermometer/whatever project I can share the results of that as well, but I have this bad habit of starting too many side projects so no promises there :p
 

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Discussion Starter · #5 ·
Too bad they're LEDs, I was hoping for something easier to solder to change the color of the back lighting.

Awesome write up though! Really informative, this is pure awesome.
Thanks, glad you appreciated it. Actually, LEDs shouldn't be that bad to replace if you/someone you know can handle soldering surface mount parts. These are pretty big LEDs and none of them seem to have the conformal coating goop on them so it should be possible. It'd be useful to know the current rating of them though, so you don't overload the chips driving them. The part I'd be more worried about in this procedure is removing those gauge needles. Like I said, I'm not sure how fragile those motors are, and getting the needles lined up properly after replacing them could be a challenge as well.
 

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Glad this is similar to the other GM clusters with the exception that the motors stay with the gauges leaving the needles in tact. Our gauges "Reset" the needles when you turn the car off so you didn't have to hold the cluster at an angle and see where the needles naturally fall before taking them off? My idea was to snag the Verano needles or the Escalade needles. The Verano chrome rings don't look as good as a RS/Diesel cluster IMHO but it looks like it would snap on to ours.



 

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Discussion Starter · #7 ·
Yeah, I would guess that Verano cluster literally uses the same circuit board. On the Cruze cluster there were extra spots for LEDs that weren't populated (but every LED that there was a hole for on the faceplate was populated, even stuff like the upshift light even though this was an automatic transmission car). I also saw the pads on the board for the pushbutton switch you can see between the DIC and speedometer.
 

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That's how it was with Buick/Century gauges. Traction control lights and performance mode LED was on the Century gauges that only applied to the S/C 3800 Regals. The difference in the gauges were the 4 needles instead of 3. Regal got DIC and a tach with a few more resistors. At this point I'm just interested in different needles, I can't stand red/orange needles.
 

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This thread is way too kool :)

...really appreciate it.
 

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Cluster is not VIN should start even without it in the car
 

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Discussion Starter · #13 ·
Cluster is not VIN should start even without it in the car
Interesting. My source for that note was this forum post by Jim Frye (http://www.cruzetalk.com/forum/25-service-issues/5413-do-not-swap-control-modules.html) with info taken from a GM Techlink document, specifically listing the cluster as one of the parts that can't be swapped (red highlight is mine). I haven't tried it since I really don't want to end up with an unstartable car, but if you have swapped clusters in a Cruze that would be an interesting point of information. Whenever I post information, I always try to be as paranoid as possible, I don't want someone to screw up their car and then be steamed at me for it :p

The Global Architecture electrical system does not allow control modules to be swapped between vehicles. Swapping control modules will result in a no start condition on both vehicles and will damage both modules due to the new vehicle security code protocol (environment).

Do not swap the following control modules:


  • Engine Control Module (ECM)
  • Radio
  • Body Control Module (BCM)
  • Electronic Brake Control Module (EBCM)
  • Sensing and Diagnostic Module (SDM)
  • Transmission Control Module (TCM)
  • Electronic Climate Control (HVAC)
  • Electric Power Steering
  • Hybrid Powertrain Control Module
  • Vehicle Communication Interface Module
  • Instrument Panel Cluster"
 

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Well... There go my hopes of getting the bigger, more detailed center screen in my Korean spec Cruze... Woulda love to have the Verano cluster, looks way more "chill" and would go great with my ambient lights :( but the dealer might be able to reprogram it, just for reference, how much did the cluster cost you?
 

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Cool. I wondered if the cluster had it's own static RAM and it appears it does. The ECO game display is probably computed by the cluster's CPU and stored in the cluster's static RAM.
 

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Oh well! So much for disabling the "shift" light.

Sent from my last surviving brain cell
 

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Discussion Starter · #17 ·
Around $30 but this was a junkyard pull and had a few minor scratches (that could probably be polished out with good plastic polish if done carefully). I imagine a brand new one from a dealer would be substantially more expensive.
 

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Can't believe I missed this until now! I disassembled the one from my old Excursion- the diesel models had a wait to start/glow plug light that also came as a dummy light in the gas models. With a small pen-type soldering iron, I wired a jumper from another warning light that flashes on/off at startup to the LED that was there and not connected. Worked fine until I sold it!

I can post some pictures of what that one looked like from my home computer, if you'd like. It used regular bulbs for the main illumination (maybe a half dozen total), but all the other warning lights were LED. That was 2002 vintage, and the cluster was essentially manufactured the same otherwise.


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Cool. I wondered if the cluster had it's own static RAM and it appears it does. The ECO game display is probably computed by the cluster's CPU and stored in the cluster's static RAM.
Seeing this, it appears to me that it's possible to flash it in our 2012's with new software to correct the 50mpg limit.....but can/will anyone do it?
 

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Wow, this was exactly what I've been looking for. Thanks so much! I was going to try and use 2013 Chrysler gauges from a 300 in my 69 Camaro. The gauges are beautiful and better looking than anything i can find. But it looks like its not possible. I was hoping the gauges were surface mounted and could be removed but if it looks anything like this one it's not possible. I'm an electronics engineer but it looks like waaaaay more work than its worth and still may not be possible.
 
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