Best I add a disclaimer, in addition to the usual one on the right.
Don't try this at home. I will not be held responsible, under any circumstances, if you damage your car. This requires accurate soldering to delicate and tiny components.
Right, having got that out of the way....
We'll start with the binnacle lighting first...
So, open the bonnet and disconnect the NEGATIVE pole of the battery. Done that? Good....
Close the bonnet and arm yourself with a No.1 and No.2 Philips screwdriver, and a 10mm spanner or socket, a good quality soldering iron, some solder, desoldering braid, decent tweezers, 10 off PLCC-2 type SMD LED's and 50 off 1206 SMD LEDs in the colour of your choice.... oh and a sewing needle (yes, really) and a bit of connector block.
After a bit of jiggling, remove the cover....
... to expose 2 10mm bolts....
... gently easy the instrument binnacle forward to allow better access to the wiring, and remove the connectors, starting at the top. Each connector has a little catch. Once the catch is pressed, the connector should come out of it's socket easily...
Don't worry about noting where all the connectors came from, as each one is unique and will only fit in one socket.
Cleanliness is the key here, so go and wash you hands, and if you have any of those nitrile or similar gloves, don a pair now. You don't want to be leaving fingerprints on the inside of your speedo once we've got it apart....
Now, gently push in the two clear plastic catches, as shown here....
... and gently un-clip the surround....
.. remove the speedo face...
... and lift out the diffuser...
... remove the four philips screws holding the speedo electronics to the brown back & sockets.... one is a different length. Make note of which one it is!
Remove the speedo electronics from the brown back assembly. This will take some gentle prying to get the socket to release.
And place the back safely out of the way....
Now, desolder the 21 pins connecting the odometer and fuel gauge LCD to the board. Take your time. Breaking this would not be good news. Once they are all desoldered, check each pin can wiggle a bit in the hole with the needle, and lift off the while plastic front, along with the LCD. Clean up the holes, by warming the DIY hole clearing tool with the iron, and inserting it into the holes, pushing out any remaining solder. Clean up with the braid, and breathe a sigh of relief.
PLCC-2 LEDs have a small cut out in one corner. This marks the cathode. There is a small arrow printed next to each LED and the cut-out must be at the pointed end of the arrow, as shown in the picture...
Heating the LEDs for too long with the soldering iron will destroy them, which isn't much of an issue when removing the old orange ones, but you want to be careful when soldering the new ones in place.
Once this is done, carefully reunite the LCD display, still on the white surround with the electronics are resolder it in place. Replace the electronics back into the rear cover, making sure the socket seats home, and replace the 4 philips screws, ensuring the long one goes back in the right hole. Replace the diffuser, and fit the face. When pushing the pointer back on, fit it pointing towards 110 MPH, and once seated move it round to 0.
Replace the black cover and the clear cover. Done.
Ignore this bit if you haven't got a tachometer (rev counter).....
Remove the philips screw in the rear of the tacho, allowing it to be pulled out slightly.
Unclip the black plastic surround and remove the surround and plastic lens in one piece...
Remove the pointer with a piece of wire or string in the same manner as we removed the speedo pointer.
Undo the two screws securing the face to the speedo...
Remove the electronics and face in one piece, disconnect the plug, and remove the two screws.
Replace the two LEDs shown, remembering the arrows...
and reassemble.
Good eh??
But we're not done yet!
Let's deal with the radio and heater.
Remove the screw.
Get a credit card or something (I've got strong finger nails!) behind the cowling, and pull it off. It shouldn't put up much of a fight.
4) Remove the pulgs and sockets from the radio (one white, on black (have little release levers on one side) and the aerial plug (just pulls off)) , and the heated rear window switch, hazard warning switch and (if you're lucky) the air con switch (have release buttons on the top or bottom).
These are green white and black respectively. Cart the whole assembly inside to the operating theatre.
This requires use of 14 fingers, or some choice expletives, or both.
12 fingers only required this time, also fewer expletives.
Remove 4 screws from sub panel and remove.
1206 LEDs are tiny!
Remove a new diode from it's packaging to examine it. Marked on it somewhere is it's polarity. The mark will indicate the cathode. In the case of my diodes, there was a green mark on the underside. This pointed to the cathode.
Repeat for the other 16 diodes on this board.
Put the board to one side , it's time to tackle the display board .... "What's so tricky And?" I hear you say .. it looks similar to the other PCB .. unfortunately there are 12 diodes UNDER the LCD crystal display, so it's got to come out.
Desolder the two multipin connectors to the display, just underneath the CD slot. TAKE YOUR TIME. The display crystal is very fragile. One crack, and it's game over. I chose to flood the connectors with solder and run the iron up and down the whole length until every joint was wet, the display will then gently come out. Solder wick is another option. Once the display is out , put it somewhere safe.
Change the diodes in the same manner as you did on the first board.
CAREFULLY re-fit the display. Don't forget to twist the tags and solder the can.
If you have a bench supply, plug the boards in and power up to check it all lights up nicely. You'll need to connect +12 Permanent, and +12 lights.
Damn, that looks good....
Right. That AUX socket on the front... what a pain. Lead from your phone dangling all over the place looking untidy... Fancy moving it somewhere sensible? Read on.....
It's uncut here...
Turn the PCB over, and connect a piece of twin and screen cable to the points as shown.

Replace the sub-panel, and the main display PCB, and carefully route your new cable out of the front... it's tight , but mine fitted.
Refit the radio in the dash, again routing the new cable. I chose to route mine to the rear of the clutter box... You'll need to solder a 3.5mm stereo jack to the end, tip is left, ring is right, and sleeve is ground.
I cut the tops of the LEDs in an attempt to diffuse the light a bit, otherwise you'll end up with two spots. Not a good look. Note the 780 ohm resistors.
Undo the panel mounting screws...
...and hinge the panel forward. You will see the old bulbs in there holders, just pull 'em out, and fit the new ones or solder in your LEDs. If they don't light, you may have them in the wrong way round. If the light is still focussing as two spots, just bend the LEDs so they face away from the front. This is easier if you have soldered separate LEDs, as I did. Once it's nice and even, screw the panel back in place, and refit the radio... Give it a try.... Nice....
... except for the headlamp aim switch ... still orange... nope, it'll have to go....
Remove the philips screw holding the outer dash on....
Pull the dash down, and pop the switch out, un-plug it and back to the operating theatre....
Pull off the cover.....
Cut off the orange LED.
... and solder in a PLCC-2 diode in it's place, with the cut-off corner facing the outside edge.
Push the cover back on, and refit the switch and dash.....

... or pink if you prefer ;)
Thanks to Hanna for the pink pic. White looks good too!
Ye gods MR a of the D. Just how brave can you get?
ReplyDeleteThis magnificent project is so full of caveats and pitfalls that I'd rather attempt to gnaw one of my legs off than attempt this micro surgery. I always said that you were wasted, but really! Eyesight is so important here, so is a steady hand and patience, sadly I lack all!!! another classic, but sadly this one Andy I'll avoid.
Thank you for the most entertaining missive Sir!
Hii! do you have some order information of the LEDS? PLCC2 LEDS and the 1206 LEDS?
ReplyDeleteYou'll find them commonly available from all good component places, and eBay. Vf isn't that important, current limiting is installed on the boards. I've not found any that don't work...
DeleteVery pleased to find the pinout for the aux socket as mine has been banjaxed by a careless former owner and I can't find a replacement. I'm going to have to solder a cable onto the PCB but what I'm not clear on is why you need to cut that track? Also will the CD player still work? Many thanks, best wishes Andrew
ReplyDeleteThe track is cut so the unit "sees" the input all the time, so you are able to select AUX with no physical jack present. Without the cut, the contact remains shorted to earth, and the unit fails to recognise the aux input. Hope this helps.
DeleteSuper-helpful, many thanks. Beats me why they need switching in the socket as well as presumably an electronic source switch activated by the button but there we are, as I can't seem to source a replacement socket anywhere a cable looks like the answer. Great blog!
ReplyDeleteI suppose it's a little unnecessary.... I blame the person who wrote the firmware... you know what software people are like ;)
Delete;) I realised in the night that as I've remived the old broken socket from the pcb I won't have to cut the track as those switch connections are now open circuit anyway. Thanks again for this great post which encouraged me to take the stereo apart.
ReplyDeleteThanks for this I just want to change my left indicator led as it's stopped working, possibly it's only a dry solder joint.
ReplyDeletewhy do you need to desolder the 21 pins connecting the odometer and fuel gauge LCD to the board?
ReplyDeleteTo change the LED's beneath it.
DeleteIs it possible to get white scale on rev meter and leave orange/red pointer?
ReplyDeleteHi Adam, It's actually very difficult to change the pointer colour.
DeleteFantastic sir Thank you
ReplyDeleteSuperb guide. Shame there aren't more like you! Any idea what the heater illumination bulbs are (probably not if you've replaced with LED's)? I can't seem to narrow them down online.
ReplyDeleteHi. I was wondering why you only replaced 4 LEDs on the speedometer when there is a lot more than 4. Do the others have any affect on the speedometer, and do they need replacing too?
ReplyDeleteOnly 4 are to do with the back light colour. The others are the warning lights.
DeleteHi Doz,
ReplyDeleteThe aux port on my aygo needs replacing. Do you have any idea where I could find the aux receiver component?
Sorry, I have no idea... maybe source a secondhand (broken?) unit, and swap out the front panel? I've posted this here, just in case anybody else knows.... Maybe worth sending Calrion an email??
DeleteJust finished my conversion to blue LEDs today. This post was of immense help, thanks very much!
ReplyDeleteWell done Xortex. It's not an easy task... be proud of your work!
Deletegood guide...can i ask, theres only 2 led on the rev counter ? which one lights the needle i wanted to have orange/red needles ...thanks
ReplyDeleteThere's no separate led for the pointer. I did see one guy had bonded an led to the needle, and supplied it with power with some very thin wires. Can't see that being too reliable though...
Deleteah thats too bad...did you ever try white led...i was hoping to keep needles orange , thanks
DeleteYou shouldn't have trouble with white. Each diode has it's own resistor and the Vf isn't much different with white vs blue.
Deletethanks , have you tried any other colours that light up well and the needles look ok....i dont want to end up with a odd needle on the rev counter ...was thinking maybe green?
DeleteI haven't ... I did blue , white and pink. It was a long time ago now!
DeleteDo you know the colour of the original LEDs you are replacing, are they cool white, pure white or warm white? thanks for all of the great info above.
ReplyDeleteNo idea. You'll need a colour temperature, not just the description if you're trying to match an original. Not an easy task.
DeleteHi fo you know if the indicator led are still tge pccl 2 type and if they are white or green leds. Thanks lawrence
ReplyDeleteI don't sorry. However, I doubt the design changed during the car's production run at all. MKII C1's, Pug 108's and MKII Aygos are a very different car. Indicator LED's where green on my vehicle.
DeleteI have a 2017 Aygo (Mk2) and want to find 2 things. the seatbelt warning buzzer (want to kill it) and what resistors controlling the turn signal frequency. The reason i have replaced the old school glow bulbs with Hi-tech LED Bulbs. But sadly the flash frequency is very high. (What i understand the Aygo models have no separate flasher relay. Hopefully i can just remove one resistor with an potentiometer and manually adjust the frequency. :)
ReplyDeleteThings have moved on since 1978 ... this will be controlled by the ECU somewhere. The fast flashing is due to low current consumption, and will be a programmed feature. Modifying this will be almost impossible to do. Add high power dissipation resistors across the LED lamp is going to be the easy solution. A quick calculation shows about 10 ohms, at 20 watts, although you'll probably get away with 10 watts due to the duty cycle.
DeleteOh, and the seatbelt warning buzzer can be disabled with a button press, consult the manual.
DeleteThank you for the info. i must find places, where i can mount the resistors inside the chassis. outside placement will probably corrode the resistors away. :) I check the manual about the buzzer disabling. thanks.
DeleteFantastic. I’m glad I came across this. Just did mine in white
ReplyDelete