Instrument cluster

[Ian James]

Hi all.  I have a 2005 1.0L Yaris Colour Collection.  The instrument cluster has developed a fault where the rev counter and speedo digits are missing entirely.  The only rev counter lights showing are the two red LCDs at the top of the rev range.  All other indicator lights are working, as are the odometer and fuel gauge.  I've taken the whole thing apart and there's nothing visibly wrong. I've also wiggled all the ribbon connectors and wires because when I reversed it into my drive last night, I'm sure I saw everything flicker into life momentarily.  Nothing doing.  The car and all other electrical parts work perfectly, so it's not a fuse issue.  I'd suspect a failed LCD display but then the fact that all the segments relating to revs and speed are out suggests a connection problem relating to those outputs.

 

The cluster part number is 83800-0D410.  There are plenty of variants of the part number available on eBay for £30 and just one exact match but it's almost £500 and with the age of the car, it's simply not worth spending that.  Does anyone have any ideas what the fault could be or whether the exact part number is essential?  Are there any of the other clusters that are visibly identical that would work, or is the circuitry too complex, meaning it's not possible to swap part numbers about?

[flash22]

Its a common issue and there are companies that prepare the units, the one from Poland at £500 is just a placeholder price

 

[Ian James]

Thanks.  What do you suggest?  Put an offer in on one them?  Or is there somewhere that will fix mine?

[flash22]

Is the part number from your speedo on your car ? or one you have looked up ?

[Ian James]

It's the one from my car.  It's on the label. 

[flash22]

https://www.ebay.co.uk/itm/TOYOTA-YARIS-I-TACHO-SPEEDOMETER-COMPTEUR-83800-0D410/323978536626?epid=21009415984&hash=item4b6ea026b2:g:D30AAOSwStBaCZCe

put an offer on it

 

[Perfection]

I remember I bought one for my 2010 Yaris and it costed around £200 from dealer. So it's worth asking the price.

[flash22]

The Mk1's use a VFD (Vacuum florescent display) and use a high voltage, things get hot and you end up with dry joints - the voltage reg and control transistor can also go bad

[Ian James]

Thanks both.  I've put an offer in and will check a dealer price when they're open.

 

I did have a good look at the joints and couldn't see anything obviously wrong but then I'm not an electronics expert.  

[Perfection]

One thing you can do is to use a freezer spray and spray at the circuit board and components joint to see if it comes  back to life. If it does, then you likely have confirmed there is a dry joint. You can just reheat the joint with an iron.

[Ian James]

Thanks

[Perfection]

Try to have the instrument cluster opened up and connect it up and power it up when you spray the freezer to look for any sign of life. BUT be careful not to short anything out.

[Ian James]

Thanks.  I've narrowed it down to the circuitry on the base of the unit, rather than the ribbon circuit that runs around the back.  The central display works with just the single multi-pin connector at the side being connected and the two on the back (that feed the ribbon) disconnected.  It can't be a failed LCD-type display panel because all of the rev and speed elements are not illuminated, so it must be a connection to the display for those elements.  The trouble is, the circuit board that feeds that section is hideously complex, so not something I could even start to work on.

[flash22]

its in 2 parts the display board and the control board, a dry or cracked joint will do it, what you only may see with a strong magnifying glass

As I said above its A VFD display, its not overly complex

I would check the ribbon between the 2 pcb's for continuity and reflow the joints then reflow the pins on the display with fresh solder

[Ian James]

Thanks.  Are the two boards you mention the horizontal one on the front of the unit base (control board) and the vertically-mounted one next to it on which the VFD display is mounted?  There's a short ribbon connector between the two of them.  Is that the one I need to be checking continuity on?

[flash22]

yes

it should look like this

borrowed from digital kaos

 

 

[Ian James]

Yea, that's exactly it. 

[Ian James]

Bit of an update.  I went to put the cluster back in place this morning so I could move the car into the garage and all the display was back on again!  It then went off after 30 seconds so I took it out and wiggled the two connectors at the rear and it flickered into life again, so it looks like it's a loose wire or dry connector there, rather than in the cluster unit itself.  I made sure each strand of wire was properly in place and it seems to have done the trick.

Whether it's a permanent fix or whether it'll start misbehaving as it's moved around whilst driving, or subjected to temperature changes, I don't know, but we'll see.  I'll keep the thread updated so if anyone else has the same issue it's something they can check.

Thanks for all your help.  Hopefully that's the end of it, but I'm not convinced....

[Ian James]

Bit of an update and a follow-up question.  It's still being temperamental and I've gradually been eliminating causes.  I'm fairly certain it's a slight crack in part of the broad electronic ribbon that wraps around the back of the whole unit, because moving that around slightly seems to bring the display back if it cuts out.  Undoing and re-doing all the indicator bulbs seems to have fixed it, and they anchor that ribbon in place as well as the white plastic pegs.

I have managed to source an exact replacement unit for £50 on eBay which I will keep as a back-up if the existing one starts to play up again.  Does anyone know if the odometer reading is stored in the cluster or in the car's ECU?  If it's in the cluster and the new unit carries the mileage from the donor car, what problems might that cause for MOT, insurance, etc?  Is it a case of me just keeping my own record of the old reading or is there an official requirement to have the correct mileage displayed?  Presumably if it's not a problem, I just let my insurer know of the change so they don't start asking questions abut excessive (or negative) mileage?

[Ian James]

Another update for anyone in the same position.  After thinking the old unit had sorted itself out, it failed again today, so I installed the second hand replacement I got from eBay.  All good, works perfectly but it's displaying the wrong mileage, so it's the cluster that holds the odometer reading.  I tried disconnecting the Battery before fitting the new unit but that didn't trick the unit into assuming the old mileage.  I've been lucky in that the difference is only 4,500 miles, my car actually having done 76,500 miles and the replacement cluster showing 72,000.  I'm inclined to ignore it since the difference is minimal and is still about a thousand miles more than the mileage recorded at the last MOT a year ago.

[flash22]

It will need the mileage corrected the mileage is logged in the bcm (becu) and main ecu aswell as the cluster

[bathtub tom]

I wouldn't bother for a fifteen-year-old car. If you do ever sell it you can point out the discrepancy to any potential buyer and even give them the old cluster. I doubt if anyone buying a car that old would get the ECU read, particularly as the MOT history wouldn't show the anomaly.

[Ian James]

Thanks both.  I'll probably never sell it. It'll be run until it's no longer economical to do so and then scrap or part-exchange it but I've kept a record of the mileages and date, as well as the old cluster so if a part-exchanging dealer wants the record, I have it.

[Mrs T23]

On 6/12/2020 at 9:37 PM, Ian James said:

Thanks both.  I'll probably never sell it. It'll be run until it's no longer economical to do so and then scrap or part-exchange it but I've kept a record of the mileages and date, as well as the old cluster so if a part-exchanging dealer wants the record, I have it.

Hi

Hope you don't mind the message - I'm having the same issue with my Yaris (04 reg) that the speed & fuel display have gone. The mechanic said 'the cables are fried' but don't know much more - trying to look for a replacement part online and wondered how you could out the exact part number etc?

Many thanks

[Peterd23]

2 hours ago, Mrs T23 said:

Hi

Hope you don't mind the message - I'm having the same issue with my Yaris (04 reg) that the speed & fuel display have gone. The mechanic said 'the cables are fried' but don't know much more - trying to look for a replacement part online and wondered how you could out the exact part number etc?

Many thanks

Hope you don't mind me adding again - just trying to help as having been there with this problem I can understand what you are going through.

There are two options to your dilemma.

1) the risky method is to try and find which speedometer online if from the same model - 1.0 petrol, 1.3 petrol or for the one I needed - 1.4 diesel. This is risky.

2) a safer method is to remove the speedometer from your car and check the label on it which has the part number. Sorry, I can't remember at the moment where the label is but I don't think it is visible without removing the speedometer - it might be though. The method for removal is simple and there are videos on youtube.

To remove the speedometer, pull the binnacle that surrounds it forward - there is nothing holding it, it just pulls out. Next remove the four screws holding the speedometer in being careful not to drop them r you will never see them again. Now release the cables and the speedometer will be loose in your hand. Honestly, it really is that easy. I did play safe though and disconnect the Battery.

Best of luck.