1999 Chevy Blazer Coolant Leak and Flasher Relay

This is actually 2 questions. 1) I took the blazer to a radiator shop for a cooling system flush and was told the coolant level was low. There are no obvious leaks and I haven't found any coolant on the snow or pavement where I park. I do get an odor of coolant in the vehicle when I start it. The coolant system pressure checked fine. He said my oil was just slightly overfull but nothing to be concerned with. The oil looks fine and the antifreeze, while dirty and definately needing the flush, was not oily. Does this sound like a head gasket starting to go or could it be something else? 2) There is a clicking coming from the relay behind my glove compartment. It sounds like the turn signal is on but no lights are on. Turn signals and flashers work fine, no bulbs out. This clicking is intermittent but when it is clicking the noise stops when I apply the brakes then starts again when I let the brake off. My mother-in-law is starting to accuse me of putting a bomb in the glove compartment when I give her a ride. I have seen other people with this issue and they said changing the relay doesn't help.