[V8] instrument cluster issues

[Mike Arman]

Ahh yes, the good old days . . .

Flaky instrument issues are often traceable to bad solder joints on the interconnect pins between 
the PC boards in the cluster.

These were wave-soldered when they were made. The issue with wave-soldering is that if you get it 
hot enough to solder the big parts, the small parts melt, and if you keep it cool enough so the 
small parts don't melt, the big parts don't solder properly - cold solder joints, resulting in 
intermittent connections and strange gauge readings. The 100% definitive diagnostic is if a whack on 
the padded dash above the instrument cluster fixes it, or any part of it, for even a short time, you 
have cold solder joints in the interconnect pins.

Common problem, and not just in our finicky, geriatric V-8 Audis.

If you examine the solder joints with a jeweler's loupe, you can see the bad ones. Failing that, if 
the pins wiggle in the PC board, the solder joint is bad.

Cure: remove the instrument cluster (try not to drop the screws at the ends and center of the dash 
pad down into the nether recesses, you'll never see them again), take it apart (gently), and using a 
small soldering pencil and rosin core solder, redo ALL the interconnect pins. Make sure not to 
create any solder bridges between adjacent pins.

Now is also a real good time to replace the various burned out instrument and dash light bulbs 
(black base, white base, etc.) and squirt the instrument light rheostat with a non-residue contact 
cleaner.

Assembly is the reverse, takes a couple of hours round trip and isn't difficult. Cautions are don't 
drop any of the hardware, and there is ALWAYS another multi-connector plug you have to find before 
the cluster will come out. If I recall correctly, you don't have to remove the steering wheel if you 
hold your mouth just right. (No promises on that, if you DO have to pull the steering wheel, 
disconnect the air bag power connector FIRST.)

Alternatively, you could buy my fully working, properly soldered instrument cluster for a bargain 
price of $1,750 or so, and I'll throw in the whole rest of the car, with relayed Eurolights, A-4 16" 
wheels, sport seats, a fresh timing belt and all the associated parts, and a HUGE STACK of spare 
everythings, many of them new. I'm near Daytona, so this is also a good excuse to visit Florida 
before it gets real hot.

Best Regards,

Mike Arman
90V8Q