si board change

I up graded my instrument cluster si board in my 1986 325es. It is the correct board. I have everything working but the tachometer and temp gauge. Any suggestion as what to do?

Most likely you've forgotten to put back or tighten the ground nut on the back of the temp guage. Double check that and it should be fine.

Take the cluster apart again and check for cracked solder joints on the pins for the large 26-pin connectors, especially the end pins.
I used a soldering iron to re-flow the solder connections to cure my cluster issues.

See these two articles for examples.

http://www.r3vlimited.com/board/showpost.php?p=2417825&postcount=26


http://www.r3vlimited.com/board/showthread.php?t=219465

Quote
Ferdinand
Take the cluster apart again and check for cracked solder joints on the pins for the large 26-pin connectors, especially the end pins.
I used a soldering iron to re-flow the solder connections to cure my cluster issues.

See these two articles for examples.

http://www.r3vlimited.com/board/showpost.php?p=2417825&postcount=26


http://www.r3vlimited.com/board/showthread.php?t=219465

Older Printed circuit boards are prone to cracked solder joints, wiht all sort of problems developing from that.
Before going out buying expensive parts, check the boards and conectors.
The tacho itself may suffer from the same, check that too.