I have a 1995 Volvo 940SE 6 cylinder turbo diesel. When I start up I get a rapid clicking from a large 80 Amp replay just above the battery, does anyone know what this relay does? Its a Volvo relay but the numbers have worn off. If I switch on the headlights the clicking stops HELP!

 

Better try Volvo Forums in GB. This here is mostly for US cars and unfortunately we have never seen a 1995 940 TD... I hate to start guessing.