instrument lights, after-run fan, and oil

["Daniel R. LeFebvre" <danbu99@bu.edu>]

concerning instrument illumination:  for a while the only way to get my
instrument cluster was to ,prior to turning on my headlights, open the
glovebox.  i was told to check the liscense plate lights because it was
rumored to sometimes be the cause of the problem.  they both worked
fine, until one time i noticed one was out.  replaced it, still no
change in my situation.  then i noticed the inside red tail-light was
out, and replaced that one.  now everything works fine.  so, just hope
my experience can put truth to rumors.  liscense plate lights (but also
other lights in the loop) can affect instrument lights, and opening the
glovebox DOES alleviate the problem, at least in my situation.


concerning after-run fan:  i think i discovered that my after-run fan
thermoswitch is shot.  the fan will come on when the ac is on (good,
right?), normally only run in low speed, occassionally run in 2nd speed
(sometimes it will appear to get 'stuck' in this high speed), and when i
shut the car off it will stop, wait one minute or so and come back on in
1st speed.  but it will run for a full 15 minutes.  someone emailed me
something about a similar problem, but said that it was so rare that the
dealer who sold him the part was shocked.  i've lost the email, could
you or someone email me average cost of this switch, and is it easy to
install?  thank you.

concerning oil change:  i recently changed the oil on my 86 5kcst 5spd.
i put mobil 1 5w-30.  no leaks, and on a recent trip to manhattan i
seemed to be getting above normal gas mileage (around 31 mpg).  also, my
boost pressure had never really gotten above 1.1-1.2, and on this trip i
for the first time hit 1.3.  question:  is the lighter weight and
fineness of the oil the cause for the improved gas mileage?  and better
turbo performance?  (in other words does the turbo spin faster and
easier because of the oil?)

final question:  i've checked the brake bomb:  about 30 pumps until very
hard.  but my BRAKE! light always comes on about one minute after
start-up.  p.s./p.b. pump makes a tick tick tick tick noise, could the
problem lay there?
thanks.
dan
86 5kcst 5spd
a.k.a. 8F-22