SI battery replace

Post Sat May 14, 2005 2:37 am

Ive a problem with my instrument cluster, in that my temperature gauge doesnt seam to work or move at all, and my fuel gauge moves up to 10 litres in any direction when I change the speed of my air conditioning fan. Ive read that bad SI board batteries can cause these kinds of strange problems with the gauges and was going to replace them.

What I wanted to know, is if I could safely solder a pair of AA 1.2V NiMh batteries in place of the two Nicad 1.2V batteries that are in it. Im very good with soldering so that shouldnt be a problem.

Also, does this sound like the likely culprit for my gauge problems? In the vehicle history, the temp sender has been replaced 4 times, to no avail, (to be honest I dont really know which one it is) but from my way of thinking, even if it is the temp sender, it couldnt explain the huge swing in fuel level when things like the fan are turned on and off.

What do you guys think?

Post Sat May 14, 2005 2:45 am

no real reason not to use nimh... but they're not as robust as nicads and start to lose charge-holding ability with age/use.

i'd put nicads in, then it'll do another 15-20 years. don't need a high charge capacity

Post Sat May 14, 2005 2:59 am

Yes you can use Ni-Mh,
and yes i would also use nicads
my batteries are half the size of AA

if you havn't already searched for the 'how to', this is a good description on doing the job...

http://www.e30m3performance.com/mainten ... _Board.htm

Enjoy...

Post Sat May 14, 2005 3:03 am

Yea, ive read the article there and it looks rather simple. TBO I just dont know where to get a set of NiCads, however I do have a heap of good NiMh batteries lying around from cameras, mice etc, so I was going to use one of them. Im not afraid of redoing it in 4 years, so thats ok with me.

But do you think it could be the cause of my temp gauge problem? the gauge just sits at the far end of cold all the time. and also the fuel gauge?

Post Sat May 14, 2005 3:12 am

I would assume so!

The most common indicators are: and irratic tach, and a mental econo-meter thingy.

but i've been reading that dead batteries cause all sorts of problems with the instument cluster.

Good luck on the fix. G.

Post Sat May 14, 2005 5:06 am

Ive taken the board out, and the batteries have brown crusty corrosion on them, though no leakage on the PCB. There is thick black silicone all over it. The thing I dont get is how the battery is actually connected to the PCB. I thought the two batteries would be connected in series, but they are not it seams. There is a wire going from each battery terminal to the pcb, and in some cases, two wires going from the terminal to the pcb.

Any ideas?

Post Sat May 14, 2005 8:43 am

Ok ive wired up an external AA battery pack, and ive put the cluster back together, one thing though....

All the wires are colour coded, except for the green connector, there is only one plug with one single wire that goes into it, and I dont know which one it goes into. Anybody know?

Post Sat May 14, 2005 11:14 am

dsio wrote:one thing though....

All the wires are colour coded, except for the green connector, there is only one plug with one single wire that goes into it, and I dont know which one it goes into.

Green plug on the back of the cluster?
I only had : white / yellow / blue ones!

Post Sat May 14, 2005 11:26 am

Just been looking around...
The green socket is for the cruise control, and sends a pulse to the ECU.
It's a blue/yellow wire with a black plug.

Post Sat May 14, 2005 11:31 am

yeah the green plug is for the cruise control, it plugs in upwards,
i can take a photo of mine if you like?

Post Sat May 14, 2005 10:38 pm

if your batteries are the small type then you have a later si board and the batteries are lithium and are not rechargable. be carefull, the lithium ones are available but are not as easy to get hold of

Post Sun May 15, 2005 7:57 am

OK, ive done it all and it works. For the most part at least.

My temp gauge is now working, as is my fuel gauge, but the SI indicator lights are weird. There is one green, and all the red / yellow ones are on and more than that, they are flashing quickly. Does this just mean I need to reset them or have I done something?

I dont care about the SI lights, and would pull them out if I had to as long as they didnt effect anything else in teh cluster by being removed. Will a reset fix this? and which pins on the multi pin connector do i short to reset it?

Post Sun May 15, 2005 7:59 am

By the way, I installed a battery holder and ran the wires out the back of teh cluseter through the vacant hole where the ABS light would be if it had ABS. Im using 2 NiMh batteries (stolen from mum's camera) and the battery pack dangles down the back of the dash down near the pedals, where its velcroed. All in all im quite pleased with it. I just need to sort out these stupid lights.