SI board batteries

[kroberts]

I've been having some annoying little problems with my POS lately. Erratic idle, bouncing temp gauge, nothing serious, just annoying. I've replaced both temp senders and the ICV in the past as a matter of routine maintenance but haven't done the SI batteries. So I opened that can of worms today. After getting my board out, I was surprised to find this...



The batteries appear to be dated 97-08. They obviously aren't AA sized batteries. Their part number is CR14250SE and they are spot welded to the board. I put my multimeter across them and I get 3.14 volts. I'm guessing this is a replacement board. I was going to do the remote battery mod but should I bother? From what I've read, including the article in this month's Roundel, my car is displaying many classic SI battery problems. Should I change the batteries anyway considering they are probably 10 years old? I've checked my grounds under the steering column and cleaned the temp gauge ground on the panel.

Any input would be appreciated,

kr

[Jean]

FWIW - Only the early clusters came with the "aa" sized batteries and those are the ones that leak more.

[kroberts]

Somebody correct me if I'm wrong. Are the batteries wired in a series or parallel circuit? If I have two, 3 volt batteries in a series circuit shouldn't I have a total of 6 volts?

[Jean]

Depends on how you measure it, if you are measuring from + of one to - of another and they are in series then you'll have 6 volts. Flip the SI board, look at the traces to be sure.

[DJB]

You are lucky. You have a replacement lithium battery board. If the batteries read 2.5V or above, they are good.

The lithium batteries are wired in parallel and diode isolated. If one battery fails the remaining battery can power the board.

The lithium batteries should last at least a decade. They will not leak when they fail, and the new style SI board should continue to work with dead batteries (although it will lose the service information every time the main battery power is removed).

Look elsewhere for your problem -- a blown fuse or loose connector.

[DJB]

Oh, the bouncing temp gauge is probably caused by worn-down solder where the gauge center contact (the sleeve around the brass stud) makes contact with the circuit board. Re-flow with fresh solder to create a new contact surface, or solder on a thin brass washer for a permanent fix.

The idle problem is either the throttle position switch not working (the computer never realizes that it should switch to idle mode), or the idle control valve.

[Schnell 318]

There is a good article in this months roundel that tells how to solder in a battery box and mount it under the dash to facilitate future si battery changes.

[eighteight325is]

There is a good article in this months roundel that tells how to solder in a battery box and mount it under the dash to facilitate future si battery changes.

Yeah, that was a really good idea, especially for anyone who leaves their car parked or in storage a lot.

[Jean]

:D I love my SIboardless cluster

[dude8383]

:D I love my SIboardless cluster

I know this is an insanely old thread but...can you explain this further? I'm interested in getting rid of the board too.