Tachometer not working

[hellgate1969]

g'day I have a HJ 47 2h diesel 12v my Tachometer gauge is not working any ideas where to start looking would be helpful and appreciated i've taken the floorpan off to get to the plug that comes off the Bell housing and checked it with a test light there's seems to be no power going to the sensor very rarely it will come on it's like there's a loose wire somewhere 99% of the time it's not working where should I start diagnosing from ??

 

[hellgate1969]

View attachment 1453660 View attachment 1453654 With the truck running there is no power to these plugs

And only the centre has power on the gauge

 

[hellgate1969]

View attachment 1453660 View attachment 1453654 With the truck running there is no power to these plugs

And only the centre has power on the gauge

 

[hellgate1969]

Just an update still having trouble anyone could give advice to be appreciated

 

[chappohj47]

Try tracking the wire under the cab to see if they have any breaks in them

 

[hellgate1969]

Try tracking the wire under the cab to see if they have any breaks in them

I check that it fine

 

[hellgate1969]

I took the sensor out of the bell housing looks fine I guess I need to check it with a multimeter but not sure how to do that

 

[too tall]

It is a hall effect sensor. You need to spin the reluctor wheel past the pickup and measure to see if it is creating a/c voltage as per the smith principal.