Suburban SF-30 runs on Bench but blows fuse while installed

furnace is out back on the bench. the furnace never was removed from the metal housing.. saw the wires you mentioned. Checked wire.. no staples.

No Spark !! under any test... do you have to have pressure to the propane side.


so.. now what is sequence of testing? I purchased SAIL switch and Limit Switch, but have not replaced yet. I afraid it might be that circuit board contoller... i will try to see how much the motor draws.