In some cars, you flick the windscreen washer
stalk and the washer sprays for 3 or 4 seconds, wipers automatically activated.
On others, you do the same and the wipers stay still but the spray washes for a
short, pre-timed period. And in yet other cars, the washer is on only when the
stalk is pulled (or button pressed), and the wipers are controlled quite
separately.
So?
Well if you’re swapping back and forth between a
car with a pre-timed wash and one without, nearly every time you get into the car with the simpler washer system, you’ll scratch the windscreen by running the wipers dry. So here’s a simple fix. What it does is run the washers for a pre-timed period each time you flick the lever or press the button. Furthermore,
if you wish, you can configure the system so that the washers will run for twice as long if you flick the lever twice (or press the button twice), three times as long if you operate the button three times, and so on.
If this was some difficult project that involved
your delving into complex wiring looms for hours, upside down under the dash and
juggling wiring diagram and multimeter – well, we honestly wouldn’t bother with
this project. But since it takes literally less than an hour to install the
pre-built module, the effort/benefit trade-off is pretty good!
eLabtronics Timer Module
The Windscreen Washer Timer uses as its control
system a pre-built electronic module – the eLabtronics Timer. This costs AUD$59
and is available from the AutoSpeed Shop.
You’ll also need a box – Performance Modules Box is suitable. The Timer is based on the eLabtronics Multi Purpose Module that is available in a
variety of forms to achieve different modification outcomes.
The module has only four wiring connections. Since
two of those are power and ground, it’s very easy to wire into place. The Timer
module can directly drive the washer pump, so no relay is needed.
Installation
There are two approaches that can be taken – the
one that is best chosen depends on the car. First step is to look under the
bonnet (hood) and find the windscreen washer pump. If the wiring to the pump is
easily able to be accessed, you’ll probably want to mount the controller under
the bonnet.
On the other hand, if the washer wiring is buried
(eg the washer bottle and pump are mounted within an inner guard
[fender]
),
perhaps the washer wiring is easier to access inside the cabin. However, in this
case you’ll probably need a wiring diagram for your car – but even a simple
generic workshop manual should be sufficient.
Let’s do the under-bonnet approach first.
Invariably, the washer pump is operated with
wiring that looks like this. The positive side of the circuit is switched, with
one side of the pump grounded (maybe not at the actual pump, but somewhere).
(Click on any of these diagrams to enlarge them.)
If you ground the negative terminal of a
multimeter, unplug the washer and probe the wiring going to the washer pump, one
side will always have 0 volts on it (ground) and the other will have battery
voltage on it when the washer pump is turned on. (Don’t forget you need to
unplug the washer pump to do this test!) From this test it is easy to work out
which is the ground wire and which is the 12V supply wire.
To install the windscreen washer timer, cut the
power supply wire to the washer pump. Feed the supply wire from the switch to
the ‘in’ terminal of the module, and connect the ‘out’ terminal of the module to
the washer.
Then all you need to do is connect to the module
to 12V (use an ignition-switched source) and ground. And that’s it!
The module has sufficient power handling
capabilities to drive all normal windscreen washer motors (for other pumps see
the breakout below) and is triggered by the standard windscreen washer pump
switch momentarily feeding power to the ‘In’ terminal.
High Power Pump?
If
you run a very high power pump (ie much higher power than typical windscreen
washer pump), you may need a heatsink on the MOSFET – check to see if this
component gets hot when the pump is running. See the end of
eLabtronics Timer for details on fitting a heatsink.
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In-Cabin
The in-cabin approach can be even easier – but
only if you have a wiring diagram for the car. That’s because you can normally
connect ground, ignition-switched 12V and the ‘in’ and ‘out’ wiring in just a
few minutes – and all to the same cluster of wires.
We chose the ‘in-cabin’ approach on the Honda
Insight to which we fitted the system.
Here is the factory wiring diagram for the Honda –
it looks fearsome in its complexity. However, when you mentally strip it down
you end up with:
Furthermore, just by taking off the lower steering
column shroud, all these wires are very easily accessed near the washer/wiper
stalk.
Here’s the plug for the Honda wiper/washer stalk.
It easily unplugs, giving access to these wires.
The correct connections made to the stalk wiring -
12V, ground, ‘in’ and ‘out’. Note that I always use different coloured wires
when making these sorts of connections – it’s much easier to keep tabs on what
is what.
The module connected to the Honda’s wiring. Note
the ‘cheat sheet’ at bottom right – it tells me what colours to connect to what
terminals. Always prepare a simple sheet to follow when working with complex
workshop diagrams.
OK, so with the module wired into place, now it’s
the time to configure it.
DIP Switch and Pots
On the board there’s a DIP switch that’s used to
configure the module for different functions. Orientate the board so that the
terminal strip is on the right and then use a ballpoint pen or a small
screwdriver to set the switches so that they look like this:
This setting configures the module to count the
number of times you operate the washer control (other options in a moment).
Now it’s time to set the length of time that one
button press will operate the windscreen washer timer. You can set this anywhere
between 1 second and 1 hour (but I reckon 1 hour might be a bit excessive!).
Again orientate the board so that the terminal
strip is on the right. Use small flat-bladed screwdriver to rotate the
bottom pot anti-clockwise at least 15 turns, or until it can be heard clicking.
(Why so many turns? Multi-turn pots like the ones fitted don’t have clear ‘end
stops’, so to make sure you’ve adjusted the pot as far as possible to the
minimum value, turn it lots of times!)
Then do the same for the upper pot – rotate it
anti-clockwise at least 15 turns, or until it can be heard clicking. OK, now
both pots have been adjusted to give the shortest possible time. Now turn the
upper pot clockwise 4 full turns. The spray time with one push of the button
will now be about 5 seconds.
If you’ve wired the system up as shown above, you
can now test it. Pull and release the washer stalk or button once and washer
should start spraying. (The on-board LED will also flash twice per second.)
After the timed period has elapsed, the LED and pump will stop operating. Pull
the washer stalk twice in quick succession and the spray should work for twice
as long. Three times – three times as long.
If you want a shorter time for a single wash,
rotate the upper pot anti-clockwise. If you want a longer time, rotate the upper
pot clockwise. If at any stage you want to cancel the spray, keep your finger on
the stalk or button for a few seconds.
If in operation you find that you want to adjust
the spray period, it’s as simple as altering the position of the upper pot. By
rotating this pot you can set the time anywhere between 0 and 60 seconds. (As
shown here, the other pot sets minutes rather than seconds.)
Now what if you decide that you don’t want
the spray to count the number of times you operate the control? Instead, you
just want a simple time extension? All that you need to do is to orientate the
board so that the terminal strip is on the right and set the DIP switch
like this:
Now the spray will start as soon as the control is
operated and will add the preset extension time to the spray operation when the
control is released. Again, you can adjust the timed period by altering the pot
position.
Mounting
With the set-up complete, install the board in its
box and then mount the box somewhere convenient – eg up under the dash. Insulate
all wiring joins and keep the wiring neat and tidy with cable ties.
Conclusion
If access to the washer pump wiring is
straightforward, the Windscreen Washer Timer is one of the easiest DIY
electronic projects to install in a car. With its ability to be configured in
different operating modes and have easy adjustment of the period of washer
extension, it’s also fun to set up. Finally, once you’re familiar with how the
module works, you can move on to using other versions of the Multi Purpose
Module for more complex car modifications.
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The
Universal Timer is available fully built and tested from the AutoSpeed Shop
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