I have a 1991 volvo 940se and I'm not sure where the relays are.

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You need a new switch.

check your headlight fuse with the switch in the on position. easiest way I have found to rule out a relay is to simply switch it out with another relay.

The symptoms you describe point to a loose or cracked speedometer cable. The cable likely needs to be replaced.

Volvo would like you to believe you need their o.e.m. and pricey anti-freeze to keep your cooling system from falling apart. NOT! Any good quality anti-freeze will perform well. Just be sure to mix it 50-50 with water when adding or changing, or using the 50-50 premix that's sold ready to use. More expensive because you're paying anti-freeze prices for water! I have used off-the-shelf anti-freeze in all my Volvos, which run 300,000 miles or more. You can extend the life of your radiator, water ump etc, but flushing the system every year or so, draining off the old coolant and adding a fresh mix.

There is a relay that controls the headlights, volvo calls it a step relay. You will have to check that power is getting to this relay. If not, check all fuses and wiring. If power supply checks out ok, you may have to replace the relay. Let me know if you need any more info or a wiring diagram.

Check the fuel relay in the fuse box they tend to burn out after a few years.. To access it. Remove the plastic cover by the cigarette lighter and remove the screw. Then remove the panel. This the big white relay on the left numbed 119 or 135. Replace it and see if this helps.

Replace your fuel pump relay.

the lights relay is located below the radio, you can get to the relay by removing the ash tray. the relay is red and round and is on the same panel as the fuses. Good luck

try pushing the 4 wires on the radio supression relay into the connector, then try starting it... does it start, run, then die? those connectors ****, i've had the same prob. have you let it huff on some ether? (starting fluid) does it come to life? that would confirm weather or not it its fuel related. my 740 i was loosing voltage to my injectors 10 volts and under, causeing them to inttermittantly not fire, caused by a bad connection at that supression relay.