testing a speedo cable

[markey b]

any way to test a speedo cable to faultfind?

i know 100% that my clocks work as they work in another car, is there a way to test both bits of the cable without expensive testers, eg. is there a voltage or something my multimeter will pick up or test?

[Scoff]

you can test it a bit like you'd test your crank angle sensor. set your meter to ohms, 1 or 2k range (something more than 500ohm anyway) and measure between the red and white wires that go to the clocks. there should be something like 200ohm between the wires (well, somewhere between 150ohm to 400ohm I would have thought). If it's open circuit then something bust. If it's short circuit then something's bust. If you get a stable reading somewhere in the afore mentioned range then the sensor and wires are probably OK.

[Scoff]

I should add that the connector should be disconnected from the clocks when you do that test.

[markey b]

thank you :)

i'm assuming that the vehicle can be stationary and it doesn't matter if the ignition is on or off as it appears to be 'unpowered' if that makes any sense

[Scoff]

thank you :)

i'm assuming that the vehicle can be stationary and it doesn't matter if the ignition is on or off as it appears to be 'unpowered' if that makes any sense

correct, you are just measuring the resistance of the sensor. short of watching it's output with an oscilliscope while the gearbox is turning you can't do much more :)

[markey b]

thank you :) last silly question, on the box, where the sensor reads in the box, there is a ridge in the sensor, is this where the clip sits or does the sensor go fully into the box, and then the clip on top? hope that makes sense

[Scoff]

thank you :) last silly question, on the box, where the sensor reads in the box, there is a ridge in the sensor, is this where the clip sits or does the sensor go fully into the box, and then the clip on top? hope that makes sense

that I can't remember!

[markey b]

i'll let you off, you've been more than helpfull :smokin: