Re: Intermittent fuel guage on a '88 E32

[erik@xxxxxxxxx (Erik Van Coops-Lotspeich)]

> Date: Fri, 10 Mar 2000 11:12:09 -0800
> From: "Murphy, Drew" <dmurphy@domain.elided>
> Subject: Intermittent fuel guage on a '88 E32
> 
> I had the original replaced with a salvaged gauge with no improvement. If I
> give the dash a good smack with my hand, frequently pops back to life. I'm
> thinking it could be poor contacts between the gauge and the dash Integrated
> Circuit card, or a bad card. The dealer thinks it's probably the card and
> quoted an absurd price for replacing it, like around $750 for the part and
> $200 for labor. What are my options? Is it hard to tear the dash apart to
> monkey with it? Are refurfished IC cards available? Is there a manual or
> site that describes dashmanelement?

Like many BMW intermittant gage problems, the problem is probably
cracked solder joints on the PCB (printed circuit board) in the
instrument cluster.

I had an E30 318i with a speedometer that operated intermittantly, and
an SI board that did not work properly.  After tons of frustration, I
found many cracked or loose solder joints on the instrument cluster PCB
(printed circuit board) itself.  After taking apart the instrument
cluster, I resoldered the joints (you could see that they were visibly
loose), and everything has worked fine ever since.

Be very careful when doing this proccedure, especially if the cracked
joints are located near sensitive instruments such as a fuel gage.  PCB
"wire" conducts very well.  I melted my fuel gage just from the heat
traveling along a wire and melting the sensitive components inside the
fuel gage.  Luckily, I had a junkyard instrument cluster as a backup,
and I was able to replace my then-melted fuel gage with the one from my
second instrument cluster.

Make sure that you hold the soldering iron on each joint only for a
short period of time so you won't risk melting anything.  This procedure
should save you lots of money, and doesn't take more than 1-2 hours. 
Please e-mail me privately if you need more information.

Erik.

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