Unhappy Neon in the rain

Hi all,
I've seen similar problems like this described, but none exactly like
this. I have a '98 Neon that gets very unhappy when it's wet. When
it's wet, if I try to start it, the lights go dim, the radio cuts out,
and the starter just "clunks" like the battery is completely dead. At
first I thought it was a linkage thing because I could normally get it
started by holding the key to start and wiggling the automatic shifter
in park or neutral. Then I realized I could also get it to start when
the battery was acting dead by simply flicking the lights on and off a
couple of times. It's like there's some poor connection somewhere
that's shorting out and flicking the lights dries it out.
Prior to starting the car however, the lights, radio, and internal
electronics work fine.

Another strange behavior is that sometimes (not always) when driving
when wet the engine runs fine (no misses, surges, etc. that I'd expect
if it was a wires or cap issue) but the electronics will just die for
half a second. It's like I turned the key off: radio goes out,
speedometer drops to zero, abs and break lights come on. Very
unnerving. I'm certain the two are somehow connected but I don't know
where to look.

The only obvious underhood thing is the positive battery terminal is
corroded. The charge is fine, but even so, I don't think corrosion
could account for all of this. It seems like there's a short some
where. Thoughts on where to look?

-Mark

 

Yes, the corrision could be causing the problem. Enough current can
flow through the corrosion to run the accessories, but the current drain
from starting is hindered by the corrosion, which acts like a resistor
in series with the strarter. Also would look at all of the ground
points and make sure they are not corroded, and all of the connectors to
make sure the contacts within are not corroded.

 

your battery is no good, replace it

 

Have you checked the individual cells? The battery itself may
have an intermittent internal short. I gather you tested the
battery also under load?

But rain alone suggests, in the simplest case, wires vulnerable
to shorting, that is, the rain acts like a shorting wire. Can't
see the rain affecting the battery unless there is some crack in
the case.

Is there an electronic test you can have someone do which would
evaluate a lot of your electrics? On old cars, I would suspect
the voltage regulator. That might also might be getting the
positive terminal by putting out too much juice at times. Is that
correct, fellows?

Just some wild guesses on my part. I'm not a mechanic.