Having gauge cluster issues??? Check here! How to prevent SI board damage!

[conecaster]

SI repairs

Greg,

You seem to have a really good handle on these SI boards.

I have been struggling to get all of my instruments working and have been able to confirm the one remaining issue is the SI board.

To this point I have installed different SI boards and get different results. Sadly I damaged the board I was replacing batteries on and got a different used board to try. Between the 2 boards all my instrument work but on the later board the gas gauge is not firing up.

I will go through the board and see if there are any bad traces, but is there a schematic that shows where the gas gauge circuit runs, if I could just get it working I'm fully functional.

Also the battery replacement went bad trying to suck solder out of the holes in the board. The rings around two holes lifted under suction. I would like to replace the Lithium batteries, this is the short battery setup and I think it best to desolder from the batteries and leave the board alone, to fragile. Have you done them this way?

Just curios.

Great write up, it is great to find your expertise here,

Thank you

[conecaster]

Just to follow up,

I removed the SI board and noticed it was very tight in the code plug I had difficulty getting it out this time. I checked the batteries and they are 3 volts,
The board looks perfect. There are no bad traces.

So I put it back together and this time made sure I had the board completely inserted in the code plug, Gas gauge came to life.

The whole cluster works now.

Hooray!!!

[Gregs///M]

Greg,

You seem to have a really good handle on these SI boards.

I have been struggling to get all of my instruments working and have been able to confirm the one remaining issue is the SI board.

To this point I have installed different SI boards and get different results. Sadly I damaged the board I was replacing batteries on and got a different used board to try. Between the 2 boards all my instrument work but on the later board the gas gauge is not firing up.

I will go through the board and see if there are any bad traces, but is there a schematic that shows where the gas gauge circuit runs, if I could just get it working I'm fully functional.

Also the battery replacement went bad trying to suck solder out of the holes in the board. The rings around two holes lifted under suction. I would like to replace the Lithium batteries, this is the short battery setup and I think it best to desolder from the batteries and leave the board alone, to fragile. Have you done them this way?

Just curios.

Great write up, it is great to find your expertise here,

Thank you

For the record, the fuel gauge has nothing to do with the SI board. It is completely independent circuit. The 7mm nut behind the gauge becoming loose gives false full reading. The solder joint and associated electrical trace is also common to crack requiring the circuit board to be refurbished.

Also for the record, replacing the batteries alone on the SI board is just a band aid. The capacitors and all transistors must be replaced. Very common for the low voltage batteries to cause rapid triggering of 30 year old transistors causing them to die. The result will be service lights remaining on with car off, key out and parasitic drain on the vehicle starting battery.

I've refurbished hundreds of SI boards from around the world including Programa, E30_dad, and other independents and never have I seen someone other than Bavarian Restoration replace any transistors. We also replace a couple other critical components for a truly refurbished SI board.