A relay is an electromagnetic switch operated by a relatively small electric current that can turn on or off a much larger electric current.
The heart of a relay is an electromagnet (a coil of wire that becomes a temporary magnet when electricity flows through it). You can think of a relay as a kind of electric lever: switch it on with a tiny current and it switches on (“leverages”) another appliance using a much bigger current. Why is that useful? As the name suggests, many sensors are incredibly sensitive pieces of electronic equipment and produce only small electric currents. But often we need them to drive bigger pieces of apparatus that use bigger currents. Relays bridge the gap, making it possible for small currents to activate larger ones. That means relays can work either as switches (turning things on and off) or as amplifiers (converting small currents into larger ones).
https://www.explainthatstuff.com/howrelayswork.html
Relays for Volvo Fog Lights
fazool » Well, I remember doing a similar thing myself once back in the day. So let me share the lesson I learned so you can benefit from it:
The fog lights (and many suchelectrical devices) consume a large amount of power. Because of that, they draw large currents to feed them. Such a large power draw needs a low resistance conductor that can handle all that current. In other words, they need a BIG wire for all those electrons.
A typical dash mounted switch is physically small and cannot connect to a large diameter wire so they run small wires. If you try to run small wires to the fog lights, they won’t be able to handle the current. They will overheat and (in my prior youthful experience) catch on fire under the dashboard.
The purpose of the relay is to be a remotely controlled switch that CAN connect to bigger wires. So the small dash switch commands the relay which flips a BIG switch.
Imagine running your battery cable through a tiny little toggle switch and on to your started motor. Flip the switch and watch the flames.
Fog Light Wires – Do I Need a Relay?
1995 850 NA relays (functions of)
Ozark Lee » The overload relays are relays that power all of the lower current devices when the key is on. By lower current I mean pretty much everything except the starter motor and the fans. There is no overload relay that only deals with the starter solenoid. Each of them deal with a variety of things.
Most of the time when the starter doesn’t reliably engage it is a PNP switch problem on the transmission. The colder it gets outside the worse the problem will be if it isn’t dealt with.
Your ’95 may or may not be pre-wired for fog lights. My ’94 is not but the ’96s and the ’98 are. The Platinum and the XC have them already. There are a couple of unused connectors at both ends of the bumper if you are pre-wired.
If you are pre-wired you need to change the headlight relay (104/108) to a part number 9148880, add the fog light relay (201 – another J relay), and add a jumper “relay”. The 213 jumper relay (9148991) is a piece of wire inside of the relay case and it is around $10.00 from the dealer. Additionally you, of course, need the lights, brackets, and the switch. lastly there are trim gaskets that go around the opening in the bumper.
1995 850 NA relays (functions of)
Last Updated on June 3, 2024
1 Comment
Power windows not working. Replaced fuse and was only able to close moon roof after several tries. Lights on dash & headlights are dimming? Any suggestions????