Technical HELP! ALL Dash Lights turned ON even when keys are out!

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Technical HELP! ALL Dash Lights turned ON even when keys are out!

masterpatfx

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Hi guys,

So it's getting hot in my country, and as last summer, I notice that when it gets hot all dash lights come on (even when car is off and key out), and when I turn the car on all gauges are down to 0 (so I have no idea what speed I'm going, how much fuel I have, if engine is overheating etc...).

I was thinking ignition switch wiring problem..what do you guys think and any way of fixing it please?

Thank you!
 
I had that happened when the ULN2803A chip (or in older models it was a similar one TD6 something) in the body computer fried. But I fried it by mistake.

You could check if it's that? Just an idea. :)
 
Hi, thanks for your reply! I cannot seem to find much information on this chip unfortunately..just to confirm, did you have a punto mk2 as well please? and by body computer you mean the ECU? where your symptoms exactly as mine please? how did you make the diagnosis and how did you fix it please (or do I need a new computer?)?

Thank you!
 
No. It's the body computer. I doubt you'll find much about it as I think it's my original work; this was my attempt to reverse engineer it https://s5tech.net/viewtopic.php?f=51&t=11178 (unfortunately in Slovenian).

For me it happened by mistake, because I fried that chip by being careless while reverse engineering. I had an unrelated problem, but when I fried that chip it caused exactly what you are experiencing. Also I've read that it happens to some cars by old age on some Alfa forum, which uses approx. same electronics and they also replace just that chip. It requires SMD soldering (SOT32 case).

I suggest that you maybe try to first connect to the body computer via CAN OBD? Although maybe you won't get any errors. :/

Edit: rereading again what you wrote, maybe you could also try to connect to the dashboard computer, also via CAN. note that for CAN, if you are using cheap OBD ELM327 you need to unsolder that pesky resistor :)
 
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