Instrument Cluster Repair

[Jolls]

Hi Team

I have a VZ SS instrument cluster that has failed. I want to teach myself to conduct repair at the component level and this is the project I intend to use.

I have managed to strip the cluster down but can't remove the circuit board from the white surround. I have removed the T10 screws but it is stuck fast in the centre. I expect it is the MFD; however, I am not sure if I need to de-solder it or not to separate the board from the surround (see pic below).

Can anyone tell me how to remove the circuit board from the plastic surround.

Next question - does anyone have cluster schematics test points so I can start my learning in relation to component level diagnosis and repair?

Cheers n Beers
Jolls

 

[Jolls]

So, I have not been able to locate schematics or any repair info on the net regarding the VZ/GTO dash. So I guess it will have to be repair from first principles.

History. March 2021 the dash stopped functioning and the needles froze in the positions they were in at the time. The car ran fine so the BCM was identified as being good. Indicators worked and the high beam indicator illuminated. Nothing else seemed to function at the time but I did not undertake exhaustive testing. Fuses were found to be good and power was available to the cluster.

This is a picture of the cluster at the time with the ignition in the on position, engine off.

Initial Repair. Repair at the time was by replacement of the cluster with a new one from LSXtreme. Simple plug in, set user requirements with the Tech 2 and drive away. It was simple and painless - less in the hip pocket.

So why do this? Given our cars and utes are aging, the availability of assembly level parts will start to dry up and costs will rise. So as I am nearing retirement I figured it was time to learn how to do the repairs myself, if possible, at the component level.

I want to have a spare dash for the VZ Crewman as we go forward as it will probably happen again. I also have to repair the current dash in the VY and look for a suitable replacement to repair to put on the shelf.

Current Information

• As repairing the cluster by replacement was successful we know that all the inputs are good.
• From the manual I have sourced the pin inputs and the associated wiring diagrams.
• At the time of the failure the indicators and high beam lights illuminated; the other warning lights unfortunately weren't tested.
• The working indicators show that the regulated supply inside the cluster is good. They function by completing the circuit to earth through their respective pin feeds, This indicates that the earth triggers to that part of the system work as does the regulated power supply. POSITIVE SIGN - the board is not completely dead.
• The Tacho and speedo also have individual earth feeds but are not functioning
• The fuel gauge is earthed via the brake fluid level indicator to park brake switch. I can't say I tested the park brake at the time so I can't determine if it is the earth side of the system that is not functioning or the feed. Most likely the feed from the BCM though.
• There is insufficient information to determine how the temp gauge functions; but I expect it receives a signal from the BCM and is earthed to the board itself.

So what does that tell us?

• I didn't do a deep enough test and examination of the cluster when it failed to determine exactly what was not functioning and why; however, I do know that the regulated power supply to the warning and indicator lights were working.
• The warning lights are triggered by external earths so if the indicators and high beam were functioning it is highly likely that the foglamps, park brake and seat belt lights, along with the illumination would also function.
• This leaves the inputs from the BCM via the UART (PIN 2) as the likely problem - this triggers the MFD, and through some internal electrickery powers the stepper motors to the gauges in the cluster itself.

So by the first principles look at it I think we now know to follow and examine the circuit from Pin 2 and see where it leads us.

More to follow once I figure out how to do that.

PS - if you are an electronics tech any assistance you can provide on where to find the circuit board info would be greatly appreciated.

Cheers n Beers
Jolls

 

[Jolls]

I have inspected the rear of the board and can't find any components that have visual defects - not bulging capacitors or burnt components. The white plastic LED mask on the front of the board has prevented a detailed inspection of that side of the board.

The multi function display and will need to be de-soldered it to remove it to complete the visual inspection of the board and enable the next level of testing.

Unless I can identify damage to the board or the tracks next step will be to test individual components and replace by failure. I trust it is a simple open circuit somewhere on the board; however, I expect it won't be a simple as that.

 

[Jolls]

So I removed the Multifunction LCD so I could remove the light mask and inspect the other side of the PCB. This is something something you will need to do if you intend to change the colour of your cluster, in particular the backlighting to the LCD.

Removing the LCD is not a straightforward exercise as it is 27 pins in a straight line. You can't simply de-solder them one by one. The method I used was to make a molten pool of solder using a piece of copper wire (I used a strand from 6mm power cable) to transfer and maintain heat. Once the pool is molten you can simply pull it through from one end to the other with light pressure. For smaller chips you can let gravity do the work for you.

The video demonstrates the method I used; except in the case of the LCD it is just one run of copper.

Removing the light mask did not unearth any damaged components or tracks. I was able to follow several tracks and identify some of the power and earth busses. I checked the capacitors and several of the resistor runs. They all passed. I don't have a oscilloscope to check some of the components or a test bens so at the moment I am at about the limits of what I can check and do.

I expect that the failure is one of two things: either the power supply circuit for the chip has failed or the chip itself has failed. I don't have the knowledge of how to check them yet. The chip is surface mounted with 124 legs so removal requires a hot air gun (that I don't own) to bring the chip and legs to the temperature required to release the chip.

So the next should be to diagnose the chip and determine if it has failed; however, the markings on the chip are too degraded to read. Maybe this is an indication of failure. Without this info I won't be able to to test it so that is the next step.

Can anyone out there provide me with the chip details and/or the cluster schematics?

I expect it is time to hunt around ePay and Gumtree for a second hand oscilloscope and heat gun. In the meantime I will will be chasing the chip details.

May be that I will have to purchase a working cluster so that I can compare notes and test points from one to the other. Again - if anyone has skills in this area I would love to hear from you. Working from first principles certainly takes time and effort.

Once I have developed the tools and skills "I'll be back"

Cheers n Beers
Jolls

 

[Aalbloshi]

So I removed the Multifunction LCD so I could remove the light mask and inspect the other side of the PCB. This is something something you will need to do if you intend to change the colour of your cluster, in particular the backlighting to the LCD.

Removing the LCD is not a straightforward exercise as it is 27 pins in a straight line. You can't simply de-solder them one by one. The method I used was to make a molten pool of solder using a piece of copper wire (I used a strand from 6mm power cable) to transfer and maintain heat. Once the pool is molten you can simply pull it through from one end to the other with light pressure. For smaller chips you can let gravity do the work for you.

The video demonstrates the method I used; except in the case of the LCD it is just one run of copper.

Removing the light mask did not unearth any damaged components or tracks. I was able to follow several tracks and identify some of the power and earth busses. I checked the capacitors and several of the resistor runs. They all passed. I don't have a oscilloscope to check some of the components or a test bens so at the moment I am at about the limits of what I can check and do.

I expect that the failure is one of two things: either the power supply circuit for the chip has failed or the chip itself has failed. I don't have the knowledge of how to check them yet. The chip is surface mounted with 124 legs so removal requires a hot air gun (that I don't own) to bring the chip and legs to the temperature required to release the chip.

So the next should be to diagnose the chip and determine if it has failed; however, the markings on the chip are too degraded to read. Maybe this is an indication of failure. Without this info I won't be able to to test it so that is the next step.

Can anyone out there provide me with the chip details and/or the cluster schematics?

I expect it is time to hunt around ePay and Gumtree for a second hand oscilloscope and heat gun. In the meantime I will will be chasing the chip details.

May be that I will have to purchase a working cluster so that I can compare notes and test points from one to the other. Again - if anyone has skills in this area I would love to hear from you. Working from first principles certainly takes time and effort.

Once I have developed the tools and skills "I'll be back"

Cheers n Beers
Jolls

Hey bro, any updates on the Cluster?