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Wayne
Wayne, Journeyman
Category: Heavy Equipment
Satisfied Customers: 8438
Experience:  34 years experiance as engine rebuild and problems.Thermo-King repair and trouble shooting.
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2003 ISUZU: A WIRING DIAGRAM FOR TRANSMISSION, SPEEDO NOT

Customer Question

I HAVE A 2003 ISUZU NQR TRUCK AUTO TRANS. TRYING TO GET A WIRING DIAGRAM FOR TRANSMISSION, SPEEDO NOT WORKING.
Submitted: 4 years ago.
Category: Heavy Equipment
Expert:  Wayne replied 4 years ago.

wayne :

Hi I'm Wayne, I will help you with this,

wayne :

good morning

wayne :

I do not have a schematic, but the speedo sensor is located on trans near drive shaft, should have 2 wires

wayne :

it is a magnetic pick up

JACUSTOMER-dqola1z0- :

its a 3 wire sensor

wayne :

OK, some are 2 some are 3

JACUSTOMER-dqola1z0- :

we have no power there.We would like to know if its a 5 volt.or 12 v.

wayne :

you get voltage into wire when the drive shaft spins, ,it will be 7.2 v

wayne :

like I said it is magnetic , creates power when steel passes the magnet

wayne :

jack up truck, unplug harness, have some in cab and put into gear , check with a volt meter

wayne :

at sensor

JACUSTOMER-dqola1z0- :

Which wire has the original volts and which is output

wayne :

what color are the wires, I don't recall

JACUSTOMER-dqola1z0- :

Black,Red and yellow with blue stripe.

wayne :

BLK, Grd, Red , power and the yellow is sensor to speedo head

JACUSTOMER-dqola1z0- :

Does the red have twelve volts or is there no power until the wheel turns.

wayne :

no power till the drive shaft turns

JACUSTOMER-dqola1z0- :

Would i be able to go check and continue our chat on the matter.

wayne :

sure

JACUSTOMER-dqola1z0- :

Thank you sir

wayne :

welcome

JACUSTOMER-dqola1z0- :

Hey wayne there is no power to any of the wires.

wayne :

then that sensor is bad

wayne :

needs to be replaced

JACUSTOMER-dqola1z0- :

If i jump the wire while the ignition is on what is the damage.

wayne :

you will blow the speed head out

JACUSTOMER-dqola1z0- :

IN addition the sensor was unplug.

wayne :

I read that as you wanted to jump power to sensor wires to head, this is not what your are saying

wayne :

you just want to jump sensor wires ,correct

JACUSTOMER-dqola1z0- :

It was working fine and some one already jumped it

wayne :

what,where did they jump wires

JACUSTOMER-dqola1z0- :

At the speed sensor harness sensor was unplugged.

wayne :

OK lets start this over,

wayne :

if you are getting no power out of sensor, it is bad , need to replace,

JACUSTOMER-dqola1z0- :

The sensor was unplugged and the wire was jumped.

JACUSTOMER-dqola1z0- :

Our original problem was the reverse light and some one unplugged the wrong wire.

wayne :

what I am saying, if the sensor is showing no voltage unplugged it is no Good , you have to have power coming out of that to make it work, botXXXXX XXXXXne

JACUSTOMER-dqola1z0- :

Okay Wayne we are going to change the sensor. From one of the other trucks.we will be back appreciate your patience it is very cold here so give us a chance to replace the sensor.Thanks

JACUSTOMER-dqola1z0- :

We will be back.

wayne :

Ok

wayne :

I will be out from 11:30 to 1 Pm, doctor appointment

JACUSTOMER-dqola1z0- :

Is there some one else we can talk to?

wayne :

Here is directions from the book to check sensor

wayne :

The vehicle speed sensor is mounted to the transmission. The transmission pinion shaft rotates and generates four pulses per one rotation. The rate at which the pulses are generated indicates the vehicle speed. The vehicle speed sensor (incorporated in the speedometer) uses the pulses to control needle movement and sends vehicle speed information to the engine control module and the cruise control unit. The speedometer sends 4096 pulses per mile and the frequency indicates the vehicle speed.

The speed sensor is located on the right hand side of the transmission tailhousing

wayne :

To test the sensor, unplug the sensor and connect a multimeter set to AC volts. If the sensor is good, you will have an output signal that varies with the speed of the vehicle.

Expert:  Wayne replied 4 years ago.

Good Morning,

Just wondering we are with this,
Did you replace the sensor,
Unit working now

Wayne
Expert:  Wayne replied 4 years ago.
Hello,
Did we solve the problem,
I did not hear from you any more,
Did you for get to Hit Accept, as this is the only way I get paid

Wayne

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