[alfa] Electrical Riddle

["iflyfisher" <iflyfisher@xxxxxxxxxxxxx>]

I posted an email on an electrical problem on my 93 Spider Veloce a while
back, but didn't get much response. I have spent some time searching for the
problem, but haven't located it yet. I thought I would toss it out again in
hopes someone could help me narrow my search.

My fuse that controls the speedo/heater blower/cig lighter blows when I hit
70-75 mph on the car. The fuse never blows below those speeds regardless of
the rpms or how bumpy or twisty the road. I can drive for months below 70 mph
with no problem, then edge the car up to 75 mph and pop. When the fuse blows,
my seatbelt, temperature, and one other idiot light (I don't remember which)
all light up. These lights are not connected to the circuit that blows as all
still work after the fuse blows. An interesting aside is that after the fuse
blows, if I turn on the heater blower and go above 75 mph, the speedo and all
works. If I then turn the blower off or drop the speed below 70 mph, the
speedo and blower stop working. BTW, the fuse will blow whether the blower fan
is on or off.

As I am not much of an electrical wiz, I am hoping some of you could help me
diagnose my problem. I have unsuccessfully chased a couple of wires, but I'd
love to narrow my search. My lay thinking is that when I reach 75, I get an
extra power surge in the circuit. If the system were grounding out, I wouldn't
think I'd be getting power after the fuse is blown when I reach 75 mph. And
why is this happening at a specific speed? I am completely baffled.

Was down in Monterey over the weekend for the Concorso and Historics. I saw
lots of beautiful Alfas. Some of you folks out there have some gorgeous cars.

Ken
1993 Yellow Spider Veloce
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided