Re: '89 Spider: power windows died

["Michael Liu" <mliu@domain.elided>]

> From: Bpnmrice@domain.elided
> Subject: Re: '89 Spider: power windows died
>
> Ron King had both power windows on his 89n Spider quit simultaneously.
>
> the first place I would check is the relay. It may be one of the
> "few big square things" next to the fuse box. On my 86 Spider, the
> window relay is on the fuse box, top row, just right of center.
> The relay in your 89 may not be located the same, but it will be
> there somewhere. If you have the owner's manual, you should have
> a diagram showing the location.

Ron, I have an early '90 Spider, so I suspect the electrical system is
identical with yours. The fuse block has two rows of sockets for
electromechanical devices (i.e., the "big square things") across the top;
some will be occupied and some will be empty, depending on the options in
your car. Counting sockets in the top row from the left (filled or empty),
the power window relay is #4; mine is a small silver metal cube with part
number 0440 stamped on it. To confirm you've got the right one, look at the
wires coming out the back of that socket: there should be two solid pink
wires coming from one terminal, tow large black wires coming from two
terminals, and a "regular size" black wire bridging the fourth terminal to
one of the large black wire terminals.

Since both windows are inop, I would diagnose in the following order:

1. Check the main power window supply fuse (should be #1); this circuit is
always hot. Using a voltmeter or test lamp, make sure there is power on both
sides of the fuse. Often the fuse terminals corrode so even if the fuse
looks intact, you may not have power getting through.

2. Check the power window relay fuse (should be #8). This circuit is hot
only when the ignition switch is on and supplies power to the relay (thus
allowing the windows to operate only when the ignition switch is on).

3. Check the power window relay. The horn relay (position #1 from the top
left) is identical to the power window relay so you can swap it in to test.

4. Check the plug to the back of the power window switch to make sure it has
not come loose.

If still no solution, you're going to have to start tracing the power
through the wires and terminals.


> The relay is a device for handling high levels of current. The low
> power window buttons activate the high current relays which run the
> high-power demand windows.

Bob, you are correct in that *usually*, relays are used to transfer control
from low-current circuits to high-current circuits. However, in the case of
the Alfa Spider power windows, this is not true. The power window switches
directly deliver the full current to the window motors, which is why the
wires connecting to the switch are of such large gauge (and why the
switches--with their thin copper internal contacts--have a propensity to
burn out over time). The power window relay is in the common ground circuit
for both windows and its sole purpose is to prevent the windows from
operating when the ignition is switched off. That is why there is only one
relay to control both power windows.

Btw, if you ever notice one window (usually the driver's) running slower
than the other, that's a good indication that the power window switch is
getting burned out and in need of replacement.


Michael Liu
San Francisco, CA
'90 Alfa Spider
'69 FIAT 124 Spider

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