Wipers Park in the middle

I have a 1984 Volvo wagon, recently the windshield wipers have started
malfunctioning. The problem is when the wipers stop, the wipers are
in the middle of the windshield. I can tap the windshield wiper
switch to get them to go part way down. It is very distracting to be
trying to get the wipers out of the way while driving. Both wipers
work (nearly) in unison and go all the way back and forth. A few
weeks earlier the driver side wiper slipped slightly out of sink with
the other wiper but was not a big deal.

I looked at the wiper gear box in the engine compartment. The
contacts looked good, but there was corrosion on what appeared to by a
ground wire. The plastic wheel that separates the three contacts
seems to be what controls the position of where the wipers are when
the power is cut to the wiper motor. The plastic wheel did not seem
adjustable. Did I miss something? Is it the motor that needs to be
replaced? Would a new motor include the gear box, contacts and wire
harness? Could the problem be caused by the switch on the steering
column?

What is causing this problem and how can I fix it?

Thank you in advance.
Austin
Volvo 240 160,000miles

 

I don't know any details of this specific model - but the general principle
of self-parking wipers is as follows:

When the switch on the column is ON, the motor is powered, and runs
continuously. There is an additional feed to the motor which by-passes the
column switch, and which connects via a rotary switch (or equivalent) inside
the motor. This switch is ON for most of the cycle, but goes OFF when the
blades reach the park position. Thus, when the the column switch is switched
OFF, the motor continues to be powered by this additional feed until the
park position is reached - when it then stops, until next activated by the
column switch. Hope this makes sense!

If the blades stop wherever they happen to be when you turn the column
switch OFF, it means that there is a fault with the alternative feed and/or
rotary switch.

If the blades continue to move when you turn the column switch OFF, and
always stop in the same place - but the WRONG place - it means that the
rotary switch is out of adjustment, and is opening at the wrong part of the
cycle.

Armed with this general information, you may be able to diagnose what is
wrong in your particular case.

HTH,
Roger

 

by Austin Kampamnn dropped his wrench, scratched his
head and mumbled,

On the bottom side of the wiper motor (inside the car, above the
insulation panel) there is a crank arm that drives the wiper
"transmission." The arm is held in place by a double D shaped shaft end
and corresponding hole in the the crank arm. The assembly is secured with
a single six mm (10mm head) screw. The screw has loosened and the crank
arm has shifted on the shaft.

Individual wiper blades are secured to the separate wiper pivots via a
taped shaft and an 8 mm nut (13mm head). The nuts work loose over time
and need to be tightened. The idea of the design is to prevent internal
damage to the transmission when the car is started in cold weather with
the wiper switch on and the blades frozen to the glass.

Bob