My '83 533i has had an on and off (mostly off) issue with the speedo and instrument lighting not working since I bought it a couple years ago. Additionally there was a battery drain on the fuse and the SI lights did not light up accurately i.e. one day it might be a single green and the next at the red. Also very occasionally there was a weird frantic clicking from the instruments.Seemed likely the SI batteries had leaked and were causing havoc on the board.
Bought a cluster on ebay and pulled mine. Mine had significant corrosion on many of the connections and one of the ribbon cables (though it looked like someone had replaced batteries and replaced odometer gears, go figure). The ebay one had leaking batteries_BUT_the corrosion hadn't traced up the wires and circuits yet but its odo had melted gears. So I put my speedo into the newer cluster, my plan was to order one of the SI bypass boards you can buy on ebay/amazon Anyway. After reinstalling the new cluster everything worked again! Dash lights worked, speedo worked, no more battery drain when the car was off, SI lights weren't lit at all but that's fine going to bypass them Anyway, drank a celebratory beer and called it a day. Sun was out so thought I'd go for a ride over lunch today-and speedo is back to not working. Too bright out to verify if dash lights are also back to being on the fritz, I'll check that tonight.
My thought is still to replace the SI board with a battery bypass board but I'm pretty stumped on next steps otherwise. Not sure how everything was working a few days ago and is now back to the way it was. I know there's a lot of pieces to this puzzle but if anyone wants to help me think through massively appreciate it.
Intermittent Speedo/dash lights (help)
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WhiteWhale
- Posts: 1
- Joined: Apr 29, 2024 5:45 PM
- Location: Seattle, USA
Re: Intermittent Speedo/dash lights (help)
Sounds like you'll just need to do the standard grind of isolating variables and tracing faults back to their source. One thing you've got going for you is the dash lights going dead. That should be pretty easy to trace -- just a DC voltage. I might be inclined to wait until I had swapped in the new SI board before going deeper into the troubleshooting.