As I almost collect all the parts for my 606 swap I am trying to sort out the little things. One of them is the glow plugs relay. The engine came with the relay attached and the harness to the glow plugs. Now I am trying to figure out how to wire the relay. There are two plugs in the relay - the 6 prong one for the glow plugs and a 3 prong one. Those 3 prongs are marked TK, DL and 31. What goes to each of them? Ground, switched power, one of them may be for the dash light

?
Any hints?
TIA