When one turns the key on a car, and it simply goes click, click, click, a trained mechanic doesn't
proclaim a failed battery or a failed starter motor. Rather, a trained mechanic pops the hood, and first
checks if the battery terminals are clean and the connections are tight – easily solutions to a seemingly
catastrophic issue, quickly resolved.|
A large majority of power wheelchair issues that seem catastrophic
are likewise often linked to a loose plug or loose connection. Whenever a power wheelchair seems possessed,
shutting down when hitting bumps – or, even more obvious, where and error code states a disconnected
or missing component – it's virtually always simply a loose connection, not an assumed catastrophic issue.
Power wheelchair connectors have come a long way toward durability and
reliability over the past decade. The male ends commonly feature from 2 to 6 wires, which feature special
metal ends, called “pins,” that literally lock into the plastic plug housing (a special tool is required
to remove the pins from the plug if ever needed). The inserted wires are then typically heat-shrinked
to the plug body for extra security, making a strong “harness.” The plug body then features a positive-locking
clip that prevents it from coming unplugged under most conditions, and the recessed male and female plug
components create a very water-resistant connection.
There are actually
fewer – and far less mysterious – connections on a rehab power wheelchair than most realize:
Motor Connector (plugs into controller)
Left Motor Connector (plugs into controller)
(plugs into controller)
Hand Control (plugs into controller)
On rehab seating, there is, of course, additional connections running to the
If one is familiar with the locations of the controller, battery compartment,
and seating (module), it's often not difficult to inspect the connections. Further, if one suspects a
particular cable or harness is loose, simply following the “wiring” to its origin will lead to its plug,
where one can see if it's loose.
The number one cause of connector issues
is improper routing. Manufacturers nowadays design routing channels and clips into power bases, specifically
to avoid tugging and chafing on harnessing connectors, preventing fatigue or dislodging. However, through
improper maintenance or over time, ideal routing can become compromised, where plugs are pulled and wires
Hidden Connector Issues
Even when a plug appears tight, it may not have the proper
connection. Although pins lock into place, like any man-made technology, they can have issues, dislodging,
not making contact. For this reason, if one suspects a bad connection, don't merely ensure that the plug
is secure, but look in the male end, confirming that all of the pins are of the same depth, alignment,
and color (void of corrosion).
Similarly, the circuit breaker is arguable the most overlooked
– or, under-looked, as the case may be – connection on a power wheelchair. Power to the power wheelchair
usually runs through the circuit breaker, so if the connections are even slightly loose, it can cause
a low-voltage error, fluctuating battery gauge, or complete shutdown.
So, the question becomes, why don't manufacturers simply make fail-safe connectors. The answer is, because
they don't exist. A recent Space Shuttle launch was scrapped because of a failed single "connector,"
a fuse. The fact is, modern power wheelchairs endure a lot of bumping and jarring, as well as the potential
for improperly-routed harnessing during maintenance – and all of this can lead to connection issues.
However, here's the good news: The solution to many power wheelchair issues comes down to a simple
answer – check the connections.
Published 6/2011, Copyright 2011, WheelchairJunkie.com