The fuse for my signal lights keep blowing when I start the car. Have replaced the
hazard light relay, but still keeps blowing. Can anyone please help?

Most likely you have a dead short somewhere, would be my guess. I would inspect all your turn signal bulbs and sockets (back side of the socket as well) to make sure you dont have a dead short there. Could also be a wiring situation where over time a loose or badly placed wire has been wearing away and the jacket has been breached causing a short.

If it is constant you can do some testing with a multimeter for continuity on the wires to see if one has a short in it to the car's frame.

Possible bad relay as well but sounds like you already tried that.

Generally a hort is going to caue the fuse to blow, although power spike could do it too.

Finding a fault in a low volt D.C electrical circuit that uses the vehicle body and other items (e.g. engine, transmission, etc.) as part of the return circuit can be very puzzling and frustrating.

You have to develop a methodical approach, and have a clear purpose in mind of what you are trying to achieve. That is, nothing will be achieved by pulling bits and pieces out willy-nilly hoping you can isolate the fault (you may be lucky, but most times you will end end wanting to set fire to the vehicle in frustration).

Automotive circuits are generally made up of (1) a power source (i.e. battery or alternator), (2) protective device(s) (e.g. fuses, overloads, (3) control device (e.g. switch, sensor etc.) (4) wiring to circuit component(s), (5) operating devices (e.g. bulbs, relays, etc. (6) return circuit from operating devices to power source (generally back through the vehicle body work.)

This may seem stupid, but check the fuse is the correct rating (remember it has to pass a reasonably heavy current when the lights are flashed).

I would take out the fuse and all the operating devices i.e. globes and hazard/turn indicator module, then re-insert the fuse and see if the fuse blows. If it does, you have a short to ground in the wiring and there is no other way but to patiently try and pinpoint just where the short circuit is occurring (which can be very difficult and time consuming.) The Volvo service manual will give you some idea whether there are wiring connectors in the wiring harness that can be disconnected to isolate various parts of the circuit wiring.

If the fuse holds up all right then I would, once again, remove the fuse and re-connect the hazard/turn indicator module to the wiring, replace the fuse and move the turn indicator lever to (1) left, (2) right and (3) flash positions and establish if the fuse blows while the turn indicator lever is in any one of these positions (if the fuse blows - it indicates the turn indicator unit is shorting out somewhere and probably needs replacing).

If the fuse hasn't blown by doing any of the above, then install each bulb and see if the globe illuminates when the operating device (turn indicator, hazard switch) is activated. I would expect the fuse would have been blowing before this because, if the fuse blows now, it means the globe is faulty (e.g. a filament hanging down inside the globe causing a direct short - it does happen, but not often).

Hope this might be of some assistance to you.

Best of luck!

P.S. When all else fails, there is the auto electrician.

I'd go for the socket and the bulb metal holder as well. Happened to me, too. Was so blur i forgot to check the new bulb inserted. Burned so many fuses i can remember.

Thanks guys.... I tried the bulbs first, plus the relay I had already changed. I now have signals.

Thanks again, Slimbo :thumbsup:

Glad you've got it sorted and also thanks for the feedback.