NetNews Usenet Archive 1992 #30/NN_1992_30.iso/spool/rec/autos/tech/16635

Text File | 1992-12-14 | 1.7 KB | 36 lines

Newsgroups: rec.autos.tech
Path: sparky!uunet!zaphod.mps.ohio-state.edu!cs.utexas.edu!qt.cs.utexas.edu!yale.edu!yale!gumby!destroyer!csd475b!newsserv!frazer
From: [e-mail] (Matt Frazer)
Subject: Defogger and A/C compressor question
Message-ID: <[e-mail]>
Sender: [e-mail]
Organization: Environmental Research Institute of Michigan, Ann Arbor, Michigan
Distribution: usa
Date: 14 Dec 92 14:17:57
Lines: 24

Hi,
  I recently inherited a 1986 Plymouth Horizon. It only has 25K actual
miles - a real life case of the little old lady who only drove it to
church on Sundays. It's in pretty good condition, but lack of use seems
to have taken its toll too. One thing I have noticed is that when I turn
on the defogger, there is a clicking sound. This car has A/C, and I found
that the noise is from the compressor clutch engaging, then immediately
disengaging. This sure doesn't seem right. The constant cycling on and off
has got to be tough on the compressor, and it sure doesn't sound good on
that little engine either.
  Could it possibly be the battery? I'm going to replace the all-but-dead
battery next week. I'm thinking that if the compressor is controlled by a
relay, when the engine rpms drop due to the compressor load, the battery
voltage is not high enough to keep the relay engaged... Just a shot in
the dark. Any other explanations would be appreciated.

  Another simpler question I have regards engine run-on. As I said, this
car was driven by a little old lady. It was probably never driven over
35MPH. Would this be the most likely cause of the terrible case of engine
run-on it has? What's the best remedy for this?

  Thanks in advance for any help.
    Matt Frazer
    [e-mail]