Dash Problems

[Guest gazza9743]

Any ideas rev counter and speedo going nuts did have the glow plug light on have changed the brake light switch and this fixed that but now or should i say the rev counter and speedo are very erattic and the abs light is flashing on. I have only changed the black switch one thing, what is the blue one for and what the heck is the switch on the clutch for my vehicle does not have cruse controll.

[Guest gazza9743]

I have sorted the problem it was an earth problem on the main engine earth strap.