Tacho stopped working

[Benengel]

Hey team.
On my home from the shops today my tacho decided to stop working.
1st and 2nd gear seems to work fine every other gear wither the tacho stays at last rpm of just reads 1-1500rpm lower theb it should.
If clutch is in or in neutral it works fine?

 

[Old.Tony]

While I've never heard of it causing this, could it be your neutral position switch?

 

[happy john]

I’ve had this before after some deep water crossings. I thought at the time it was some sort of earthing problem. Whilst I have never heard anyone speak of this issue Tony’s suggestion is very plausible.

 

[Benengel]

Yeah i thought so too. I tried each gear with the heat switch on
and it worked as it should have.
Gave the truck a service and took all the batteries off just to try reset everything and I'll test it out this week

 

[tony d22]

Check Crank Angle sensor and tach sender?