I have an L553 skid steer and last year it started getting hard to start. Last summer I put new glow plugs in it but it did not make much difference. I don't think I am getting power to the glow plugs. Is there any type of relay that the power has to go thru before it gets to the glow plug? If Take a reading off the short rods that connect the glow plugs on the top cap would I get a voltage reading and if so what should it be? I don't think it is a compression issue because it does not lack for power. Thanks for any help.