Many thanks for the reply, very good to see there are still people following this topic.I had the same fault and ended up sourcing a brand new, old stock cluster for £150 (SEAT wanted over £400) That then gave me the chance to troubleshoot the old one, without the worry of bricking it, and although I didn't test it at any great length, it definitely seemed to have sorted the problem when I took it out for a short test drive.
Basically I reflowed the 2 green and blue connectors that are circled in the attached pic. DON'T attempt it unless you're fairly experienced at soldering and feel capable of doing it without damaging the board or bridging the pins though!!
Use a suitable iron (I was worried about melting the plastic connectors if using hot air) and plenty of good quality flux and it's a fairly easy job. If you don't think you're able to do that safely then there are companies that you can send them off to to be repaired.
Hope that's some help.
View attachment 25471
Just to recap the symptoms:
1. Cluster works perfectly with car running, responds to brightness adjustment, no flickering, no spurious warning LEDs lit.
2. When ignition is switched off, the cluster switches off including the backlight.
3. A few seconds after locking the car, the cluster backlight comes back on and stays on draining the battery.
4. Pulling fuse 15 (5A) kills the backlight, but also kills time and mileage LCDs (which are supposed to stay on, but without backlight).
I have taken out my cluster (Seat Leon MK1 1M0920902A) and did the following:
- a thorough inspection of the back of the green and black connectors. Cluster is nice and dry.
- cleaned up all soldering joints for these connectors (minor corrosion only). Visually all pin soldering looks solid, no cracks etc. Checked continuity with multimeter between permanent battery live, switched live(s), ground, and all other pins.
- attempted a bench test (out of the car, on kitchen table) of the cluster by ONLY connecting pins 9A and 24A to ground and 23A to battery positive. All other pins not connected, incl. Green connector (with can bus) fully out.
Cluster backlight comes on immediately.
A bit stuck at this point:
- visual condition of the pin soldering, tells me green and blue connectors are fine. Also no measured shorts between permanent and switched battery live (at connectors at least).
- backlight is on when just permanent battery live + battery ground is on. This tells me that EITHER the cluster has an internal pcb short somewhere, which cause the +12V to jump to "ignition switched side" OR cluster requires a ground/voltage/signal on some other pin(s) to force the backlight to sleep.
Dear fellow members, please help!
Note (copied from another forum and verified per wiring diagram):
KLINE 25A
CANH 27B
CANL 28B
12V 1A (DIN 15, battery switched live)
12V 23A (DIN 30, battery permanent live)
12 30A (battery switched live from ignition switch)
GND 9A (DIN 31)
GND 24A (DIN 31)
A = Blue connector
B = Green connector
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