Since day one, the first thing I noticed about my Spider was it's
medicore windshield wipers. I tried several things to boost the speed
of the wipers. Everything from fixing the ground, cleaning/ greasing
the motor, linkages, etc. All of this helped but it still wasn't up to
par. I finally came to the conclusion that the problem was the motor
itself. This whole system was marginal to begin with and age only makes
it worse. But thanks to Ebay I was able to window shop for a new motor
that would bolt right in. Finally I found that motor.
The motor I used came from a 1977 VW Rabbit. I got this particular
motor for $9.00 plus shipping. If you decide to look for one of these
motors, any motor from a mid 70s VW or Audi up until the mid 80s should
work. Just be sure it uses five wires. Also this wiper
motor uses a relay style connector so it was easy to wire up. This
motor is made by Bosch and bolts right in. However requires a slight
modification so that the wipers will park and allows the use of the
intermittant wiper function. This isn't the only motor that will work
but seems to be the most readily available and without much fuss to
I was also able to modify a wiper motor from a Yugo which also works
much better than the Marelli motor. But after some bench testing I
determined the Bosch motor was the best choice. The original speed of
motor was 46 RPMs on fast. After cleaning the Bosch motor and greasing
the commutator bearing and reduction gear I got 73 RPMs when bench
tested! Actual speed on a wet windshield was timed at around 65 RPMs. A
significant increase in speed. Also the wipers
no longer drag across the windshield when trying to swipe the
windshield of dew in the morning or mist.
If you haven't checked out my webpage on restoring your electrical system, do so now. I'd also recommend cleaning the wiper
linkage to make sure there is no resistance in the system.
Before doing anything, it's best to dismantle the motor, inspect it,
give it a good cleaning and repack the reduction gear with grease. I
cleaned mine in kerosene but this may not be a good idea on the
commutator (the piece with the copper windings) because this is coated
with varnish. This varnish protects the windings from shorting out.
I'd recommend using an electric motor cleaner available from Autozone.
The rest of the parts can be cleaned with kerosene. I used high
temperature wheel bearing grease for disc brakes. Once again it might
be better to use some sort of
grease especially for electric motors. But don't ask me where to get
it. I also applied grease to the commutator bearing.
While you have the motor apart, inspect the brushes and the copper
portion of the commutator. If anything looks excessively worn, get
another motor. They are cheap and not worth rebuilding. If they can be
The easiest way to put the motor back together is to pull the brushes
apart and insert the commutator into the gear head. Then stick a
flathead screwdriver between the reduction gear and the screw. This
will prevent the magnets in the housing from pulling the commutator out
of the brushes.
The Bosch motor uses five wires. The 1979+ Spider uses six wires. I
believe the 1979+ X 1/9s also use six wires. I wish I had more
information to back up my claims but I think Fiats from 1978 and back
use five wire wiper motors. Somehow I accumulated several Marelli wiper
motors over the years and I have some that use only five wires. So no
matter which model or
year Fiat you have, you can make this motor work on your car. The trick
is to figure out which wires do what on the harness and go
from there. Other than my Yugo which uses five wires, the only Fiat I
own is a 1980 Spider so this is what I'll concentrate on. If you own
say a 1981 X 1/9, these wires should have the same function but are
Blue/Black --> Always hot when ignition switch is on
Blue/White --> Hot only when wipers are in constant mode
Black/Grey --> Hot on both slow and fast, constant and intermittant
Blue --> Hot only on fast speed
Grey --> Hot only on slow speed
Black --> Ground
Here's a photo of the Yugo motor with the gear exposed. The Bosch motor is similiar.
Notice the fingers on the gear cover. As the motor turns each finger makes contact with a certain spot on the disc. One makes
contact all the time. One touches the brass portion of the disc briefly and the other one makes contact most of the time.
The trick was to isolate the finger that is grounded to the body and
solder a six wire to it. I took a some wire cutters and cut the tab
and bent it so that it did not touch any of the other wires or the body
of the wiper motor. Also notice that I trimmed off a section of the
motor which was used as a support bracket for the VW wiper linkage.
When I linked the wires from the car's wiring
harness to the wiper motor, I used 12 AWG wire. This may be overkill.
Just don't use anything thinner than 14 AWG.
The color of the wires on the Bosch motor do not correspond like one would expect.
Brown ---> Ground
Red ---> Slow
Yellow ---> Fast
White ----> Hot on fast and slow
Black ---->Always hot
Tab -----> Grounded to the wiper motor's body
Once the tab on the Bosch motor is isolated from the gear cover and a six wire soldered to it, it's just a matter of
connecting the wires from the motor to the harness on the Spider.
So it's like this (Bosch motor ---> Spider's harness):
Brown --> Black
Red --> Grey
Yellow -> Blue
White --> Grey Black
Black --> Blue/Black
Tab ---> Blue white
Keep in mind the Spider uses a knob on the dashboard to control the speed so I may have the "speed" wires reversed. You will
never know this on a Spider but on the X 1/9 where the speed is selected by the column switch, may show up as being reversed
so keep that in mind if this happens.
let's assume you have an older Fiat that uses a wiper motor with five
wires. Well your in luck because you shouldn't have to isolate the tab
from the wiper motor! When I removed the gear cover from a five wire
Marelli motor I discovered that one of the contacts in the park
mechanism is grounded.
Here is a photo of the Marelli motor's gear cover removed. These should
be the same on all Fiats except for the number of wires
used. On five wire motors, one of the contacts will be grounded. So
there is no need to break the tab on the back of the Bosch motor and
solder an extra wire.
Notice that one contact is fixed and is attached to a tab which can
make contact with two other contacts depending upon the
position of the wiper motor. In this position the circuit is being
completed "most" of the time. As the cam gear rotates, it breaks
contact and makes contact "breifly" with the other contact. On the
backside of the gear cover are wires soldered to these contacts. So
once you figure out what these wires do on your Fiat, correspond them
to the wires on the Bosch motor.
Since the wiring differs between models throughout the years I
cannot explain which wires goto
what on every model. But if you wish to carry out this conversion, just
send me an email and I'll try to help. I hope this webpage
OH and one more thing to mention. The Bosch motor turns in the opposite
direction as the Marelli motor. At first I thought this might be
an issue but it makes no difference. Just make sure you mark the
location on the linkage so the wipers are correctly positioned. I found
it best to turn the wiper motor on before connecting it to the linkage
so it can park correctly, then connect it to the linkage, turn it
on again, then install the wiper arms.