Technical Dead Instrument cluster on 500c

[robinma2000]

Can you guys offer advice on a dead instrument cluster. It keeps blowing the fuse. Twice so far. I've noticed that the dashboard warning lights go crazy just before. Notably the hill start warning message, and airbag warning and stop start warning. Then after I restart the car the fuse has blown and dashboard dead. I have read through similar posts, many point to the wiring loom. I have looked where it enters the boot lid and it looks good. I had a vigorous scrub of the alloys with a wheel brush, could that have disturbed anything? I also suspicious that it has gone each time when I have lowered the roof. I have previously noticed faint flashing of other lights on the cluster when indicating, which I have seen mentioned in various threads. The car is otherwise fine, lights indicators etc...The green light come on in the cluster and if I open the doors the mileage displays on the console. I also noticed the ASR light is now permanently on and can't be switched off. Replacing the fuse returns everything to normal, for a short while till it all starts again with the warnings.

Any help you could offer would be great thanks....

 

[John202020]

The fuse blowing is most likely a short, if you don't operate the roof or boot lid is the dash all good, is it only when either are moved things go wrong?
The lights flashing when indicating is a different issue, leave it for now until you've fixed the fuse blowing issue, wheel cleaning nothing to do with it.

 

[robinma2000]

The fuse blowing is most likely a short, if you don't operate the roof or boot lid is the dash all good, is it only when either are moved things go wrong?
The lights flashing when indicating is a different issue, leave it for now until you've fixed the fuse blowing issue, wheel cleaning nothing to do with it.

Tried replacing the fuse again to see if the fairies might have fixed it overnight. It lasted just a few seconds till all the warning lights lit up like a christmas tree. It stays working albeit flashing until I switch off and restart at which point the fuse is blown. May be a clue I have discovered the brake lights dont work when it has gone. But I guess it might share the fuse. I'm going to look for blown bulbs. The micro connection in the headlining for the rear led brake light looks good

 

[John202020]

There's a thread on the soft top 're the fuse blowing just down the main page with the brake light

 

[robinma2000]

There's a thread on the soft top 're the fuse blowing just down the main page with the brake light

I will search for that thanks. I have taken both light clusters off. All bulbs were good, but in disturbing the wiring i have got a better clue. As soon as I hit break pedal i get check stop lights warning on the dash. And the breaklight bulb in the near side cluster is not coming on. If I swap bulbs, the problems stays on the same side so it is not the bulb. I will see if I can find the thread you referred to. Thank you.

 

[robinma2000]

As I have discovered the issue seems to stem from the near side brake light (not all three brake lights). Would you be checking the loom in the tail of the car. Or be looking around the brake light switch in the front? I wonder where the circuit breaks into three?


The wires behind the top of the rear seat that go along behind the boot lining look ok. No obvious splits. And the wires that emerge into the back of the light cluster look fine. And the wires that are wrapped around the roof struts look ok.


I wonder if I am looking for a fracture or a bare section?

 

[robinma2000]

So I have removed the light cluster and pulled the wires through into the boot space. The last 10 inches of or so of wires split of from the main loom and feed the light cluster. These wires are showing no sign of wear or stress. Tracing it back after the wires join into the main loom I cannot see any more articulation points that could cause the issue. At the moment the NS brake light is out, and now the ns rear indicator is out, however the indicator is causing the taillight to flicker. I'm sure the issue must be in this last section of wiring, but I anticipated finding bare copper showing. Some tips or encouragement would be welcome

 

[robinma2000]

So I have removed the light cluster and pulled the wires through into the boot space. The last 10 inches of or so of wires split of from the main loom and feed the light cluster. These wires are showing no sign of wear or stress. Tracing it back after the wires join into the main loom I cannot see any more articulation points that could cause the issue. At the moment the NS brake light is out, and now the ns rear indicator is out, however the indicator is causing the taillight to flicker. I'm sure the issue must be in this last section of wiring, but I anticipated finding bare copper showing. Some tips or encouragement would be welcome

Seems two of the wires that pass through the body into the cavity behind the tail light have fractures. If I feel with my thumb nail it seems to be broken. However I have wiggled and pushed and bent and straightened and at the moment they are contacting correctly. So whilst it isnt a repair I have strapped it back together and hope the fairies do their work. Although I have bought wires and connectors to splice it properly. It will look so ugly if I patch pieces in. I might try and find a full loom, not a repair loom. And see if I can replace it fully. The picture is the last 9 inches of wire where the fracture is
It isnt bare so I still can't understand the devastating effect on the instrument cluster

 

[robinma2000]

So after a few days clear motoring today I put the sunroof down and the fuse has blown again. I therefore assume I sm looking for a cable connected to the roof movement that is capable of cutting out the brake light fuse. Feel free to toss in some ideas

 

[John202020]

Cut the cable to the central brake light(so it does not work) drive the car for a few days operating the roof as required see if the fuse blows? Never be tempted to put a bigger fuse in the slot. "If" all good maybe , rewire the central light?

 

[robinma2000]

Cut the cable to the central brake light(so it does not work) drive the car for a few days operating the roof as required see if the fuse blows? Never be tempted to put a bigger fuse in the slot. "If" all good maybe , rewire the central light?

That's not a bad shout. One of the first places I looked was the wire under the headlining, I will check it again

 

[robinma2000]

That's not a bad shout. One of the first places I looked was the wire under the headlining, I will check it again

I think I have got the little bstard. Where a wire goes around the roof mechanism