Question for the electrical experts..What would happen if the Positive and
Negative wires of the vehicle Speed Sensor.VSS.. were reversed..?
I am here looking at 98' Taurus with all the symptoms of a bad VSS, or open
circuits in the wiring harness to the Power Control Module, PCM. According
the Haynes and Mitchell repair manual description for wires and connector
terminal, the wires have been reversed. The connector appears not to be the
original, both wires are white in color, where as just about all other
sensors wires have different, bi- color coding..
Any help will be greatly appreciated..
Thanks in advanced.
The VSS is essentially a little electric generator. Measure the terminals
of the VSS to ground. (VSS not connected) If both terminals are NOT grounded,
It should not make any difference. I suppose you could always swap the leads
and see what happens. I have a old one laying around i will measure
when i get a chance. Now, if its a hall sensor or such with a pre amp, polarity
would make a difference.
"V.B. Mercon" wrote:
The wires from the harness, before the splice,(where the connector with two
white wires,) are orange/pink and grey/black, just as indicated in the
Haynes and Mitchell manual. orange/pink goes to ground, and grey/black is
hot/positive, it goes to the PCM. I have tested both and verified them. Now,
according to Haynes, Mitchell, and now Chilton,in looking at the connector,
straight on, top up, the left hand terminal is positive, and the right
terminal is negative. The wires from the harness are connected to the
connector in reverse according to color code and polarity.
When the car is cold the speedometer works OK. After about a mile or two it
goes to zero, and if I slow down the shift becomes long and erratic, typical
VSS symptoms. I have never come across a car with the wires with reversed .
The sensor tested OK.
Found the answer. Since the VSS generates AC current, it makes no difference
how the wires are connected.
Still it would be nice when components are replaced, when you give a car out
for repairs, they are put back exactly as they were.
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