just pulled the SI board - BMW Forum

yammahamma · 02-06-2006, 01:38 PM

Yea so I just yanked out the SI board and it looks fine....but I'm sure the batteries are dead....

my question is, can I drive the car with the whole instrument cluster removed? I don't really want to put it back together but I do need to drive to radio shack and buy the new batteries....and it would be a pain to put it back together and then take it apart again when I get home...

any body know??

thanks!

ldsbeaker · 02-06-2006, 06:10 PM

I would avoid it if possible....
I'm going to get all the materials together before I tear my trash apart... but then again, I have a couple backup cars...

yammahamma · 02-06-2006, 07:00 PM

Yea I would have gotten everything together first but I wanted to pull it out first just to make sure the battery didn't leak all over the board....I didn't want to get all the stuff from radio shack and then find out I need a new board all together.

But the board looks good so I think radio shack it is.

I've allready put it back together...well most of it. anything that has an electric connection is allready put back in the car. The covers and what not will be left off until I get the soldering done.

that brings my next question...I was hoping for an easy "+", "-" solder. but after looking at the board there isn't such markings, could any one give me a DIY on what to do? I've done a little soldering in my past, just real simple stuff...but this can't be to hard right?

here's some pics:

yammahamma · 02-07-2006, 10:27 PM

ummmm..so can any walk me through on what to solder to what? I don't really want to pay someone if I don't have to...

thanks!

Starmavin · 02-08-2006, 06:24 PM

Do you have the AA size or the 1/2 AA size? I don't advise soldering them in you'll damage the battery before the solder melts. For the AA size some say go radio shack and buy a AA carrier and you can solder it to the board and run the wires out to the carrier and zip tie it to a wire bundle under the dash. I do something much different. I'll get a batery plate and spring then solder them to the board then put down a small dab of hot glue so they don't bounce out from rough driving.

Don't forget I think it's the + that has two pins, if you use a spring with one lead use a wire to cross over to the other pin hole.

yammahamma · 02-08-2006, 08:30 PM

They're the same size as AA. I think I'll just do the battery holder and run wires to the board...just to make it easy for me.

the thing I find confusing is there isn't just one set of 2 pins...there's two sets of two pins and two sets of single pins....so do I solder one new battery to each set of two and sinlge pins? Did that make sense?

both ends of the batteries look like the pic I posted earlier...

john_k_o · 02-09-2006, 05:46 AM

just use a multimeter to check the polarity, there should be still a bit of power in them, it will let you know straight away. Or from memory, the side of the battery with the ring around it is positive

Carbed318i · 02-15-2006, 06:51 PM

That's a curious subject. I'd like to know if it's possible to just buy a whole new SI board? And if so, where should i get one?

yammahamma · 02-15-2006, 07:54 PM

yes it's very possible to buy a new board...I bought one today, just because no gave a for way of soldering in new batteries....so I thought instead of screwing up my board I'll just buy a new one.....the cheapest one I found was around $120 but that's after a $70 core refund...I got it from:

http://www.alleurasianautoparts.com

it's MUCH cheaper to solder in new batteries....

any online auto store should offer the SI board...

Raymond · 02-25-2006, 01:51 PM

So, I pulled the SI board and the oringinal Varta batteries were in there and marked Pos & Neg. I metered them and found one batt. delivering 0.4 V. I removed them and wired in the Radio Shack carrier and put in two Lithium-Ion AAs. I am getting the proper voltage, but the guages are still screwed up. Tach barely moves, fuel guage starts off fine then at 1/4 tank drops to 0.

Is the SI board toast, or would it be worthwhile to replace the fuel economy sender?

1989 325i Cabriolet

Starmavin · 02-25-2006, 02:41 PM

Quote:

Originally Posted by Raymond

So, I pulled the SI board and the oringinal Varta batteries were in there and marked Pos & Neg. I metered them and found one batt. delivering 0.4 V. I removed them and wired in the Radio Shack carrier and put in two Lithium-Ion AAs. I am getting the proper voltage, but the guages are still screwed up. Tach barely moves, fuel guage starts off fine then at 1/4 tank drops to 0.

Is the SI board toast, or would it be worthwhile to replace the fuel economy sender?

1989 325i Cabriolet

It may not be the SI board... The fuel guage problem may be the sending unit getting funky, the tach could be the tach itself, the OBC or wiring to them. I've seen where about 80% of the time the SI board screws with the guages when it's covered in acid and shorted out.