What’s this? (Auto electrics)

[smashweld]

connected between the feed and additional reverse lights on the truck
Not had a chance to look at bulb type etc but not sure what this is for
There’s a reverse beeper too, don’t know if that has anything to do with it.

 

[agriceng]

It's a relay, an electrically operated switch basically.

 

[Robotstar5]

It's a changeover relay.

 

[smashweld]

hmm...everything is 24v afaik, what would be the need for the relay?

As I say not looked at the beeper or bulb voltage but I’m assuming all 24v

 

[carbon]

If it’s fitted for additional reverse lights then it’s been fitted so the original wiring and fuse isn’t overloaded. Depending on what sort of additional lights are fitted depends on the extra load added to to original system. Have seen fog lights with halogen bulbs fitted but is getting more common to see led worklights used as they don’t require so much current.

 

[8ob]

Sometimes get changeover relays on the back of trucks when they are wired for trailers. Stops the fogs and reversing lights working on the truck when the trailers connected so they then only work on the back of the trailer.

Bob

 

[smashweld]

the extra reverse lights are bright so seperating them from the original wiring makes sense....there must be an additional fuse at the other side of the relay I've missed then?

interested to know how that works 8ob...how does it sense the trailer's plugged in and stop the rear lights working?

 

[8ob]

interested to know how that works 8ob...how does it sense the trailer's plugged in and stop the rear lights working?

On my trucks trailer plug (24n) there are only seven wires ( no reverse) so must be sensed/switched off the aux plug which carries the reverse,beacons,charge wire and worklights. On some car trailer sockets they have the switch in the socket that knocks out the cars fog .

https://www.12voltplanet.co.uk/plastic-continental-euro-13-pin-socket-12-volts.html

Bob

 

[ibrooks]

the extra reverse lights are bright so seperating them from the original wiring makes sense....there must be an additional fuse at the other side of the relay I've missed then?

Maybe - maybe not, depends on who installed it. There should be a fuse ideally between wherever the power is coming from and the relay but it could have been put between the relay and the lights or there might not be one at all.

 

[smashweld]

Just digging this back up....

I’ve lost the sketch I made of where the wires go

Which of the 5 terminals are inputs or outputs....or ?

There was 4 wires going in to the relay.2 of them to the same terminal....or maybe it was 1 wire going to 2 terminals, can’t remember!
.the 2 reversing lights, a feed that comes from the front of the truck that switched on when in reverse, and a wire that had been wired in to the reverse light in one of the clusters at the back (the reverse light in the cluster works without that wire connected, and so do the extra reverse lights so not sure of it’s purpose?)

If someone could tell me what the different terminals are for that should be enough

 

[MetalMonkey]

85 and 86 are the coil - so one can go to your feed from your existing lights and one to earth, doesn't matter which is which.

30 and 87 are your normally open contacts, so 30 would go to your fused supply and 87 would go off to your new lights.

Hope that helps.

 

[smashweld]

Perfect,cheers Metalmonkey.

I’m guessing either the wire from the cluster or what I thought was another reverse feed must have been the earth

 

[Robotstar5]

Here you go....

 

[smashweld]

Pretty sur an earth is an earth....but just checking...

Is it ok/normal to have the 2 earths from the extra lights and the - from the fused extra feed all on (assuming it’s fused...it goes to the front of the motor, so to the fuse box or battery)85 or 86?