Transfer Case Speedometer Sending Unit Wire Question

On a 1991 XJ, on the NP231 t-case, two wires connect to the speedometer sending unit (officially "SENSOR PACKAGE, Distance", MOPAR part number 5233 152). Its a two prong connector.

One wire is black with a blue stripe. One wire is yellow with a red stripe.

I do not own a ohm/volt meter. Hope that a patron can advise on the positive vs. the negative wire.

I assume yellow/red is positive. But assuming is a bad thing to do.

Since owning the XJ, the speedo has a glitch. It randomly, but rarely stops working until traversing over a few bumps. Same scenario with two different speedometers.

Upon attempting to install a new speedometer gear, the speedo (and odometer, by the way) quit working all together. Also attempted to re-install the old gear, same outcome.

Replacing the sensor. However, I do not know which wire is which.

From what I can see on the wiring diagrams Tan is hot, Black is ground -- obviously this doesn't help you

Looks like you're going to have to buy a $7 volt meter from Harbor freight

Heavyopp said:

From what I can see on the wiring diagrams Tan is hot, Black is ground -- obviously this doesn't help you

Looks like you're going to have to buy a $7 volt meter from Harbor freight

Click to expand...

... and learn how to use it.

Can I just turn the vehicle on and stick the wire on my tongue :laugh:

Thank you for the info!

Heavyopp said:

From what I can see on the wiring diagrams Tan is hot, Black is ground -- obviously this doesn't help you

Looks like you're going to have to buy a $7 volt meter from Harbor freight

Click to expand...

The tan/black would be the trans output speed sensor which goes to the trans computer. Only two wires to the sensor, the polarity likely doesn't matter.

rmoorex said:

... and learn how to use it.

Click to expand...

if in fact there is a positive and negative at the sensor then it will be easy to figure out which is which with the voltmeter

Set voltmeter to DC 20 volts and probe the wires -- if it reads 12 volts or whatever voltage you would expect then the red probe of the voltmeter is connected to positive -- if it reads Negative voltage (-12) then the red probe is connected backwards or on the negative wire

Thanks for the input! Got the meter. Worked! Thank you.