1985 Volvo 240. I had some electrical problems like this while ago but lights worked fine for few months. Now few days ago the indicator light sometimes lit but didnt blink even tho i didn't pull the switch. Then both indicators suddenly came on but didnt blink and only if i had the lights on. Lights off hazards worked fine but with lights on they also just stay lit without blinking. Also sometimes when the indicators worked and for example i turn on the left side indicators also the right side indicators lit but they were not as bright. Problem isn't likely in the relay because it's new and the seatbelt warning works fine and the relay is clicking (same relay with indicators). Now all tail lamp fuses blow if i turn the lights on and also indicator fuse blows if i pull the switch and same thing with hazards the fuse instantly blows if i turn on the hazards. All bulbs changed in pairs so that also isn't the problem. I have checked the wiring of rear ashtray light and one ground wire is little bit broken but not touching anything. Also that bulb works sometimes but most of the time its not working. If anybody has had this same type of problem please let me know where to start looking for the most common broken wires and also I don't really know what wiring is connected to others.
Thanks for all answers and sorry if my english is hard to understand.

(add) also sometimes the bulb failure light flickers and that was also the case before so I got that changed. Over a year ago i accidentally put too big fuse and the relay for bulb failure burned. I have to pull it out and see if it still blows fuses. The problem could be in that relay or it's wiring because right now all light fuses keep blowing.