The numbers on the electrical relay?

Submitted: Thursday, Aug 14, 2003 at 19:13
ThreadID: 6573 Views:6845 Replies:5 FollowUps:1
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I just bought some lightforce spotties today and as I am not very electrically minded I thought I would run afew questions passed those of you who are.

1. What do each of the numbers on the relay I bought today relate to? and is it neccessary to run it through relay, why?

2. The numbers and diagrams don't make a lot of sense to me but they are 85, 86, 87, 87a, and 30. I am mounting a switch in the car and it just a simple three point one that is ether on or off. The numbers on it are 1, 2,3. 1 goes to the relay (but where?) 2 goes to batery and three is ground.

3. On all of the (grounds or are they negatives?) needed when wiring spoties (one from each light, one from the switch, and one from the relay (I think) can they all be put to the same ground? and where is a good place to put it on the car.

4. I have some 30 amp wire will this be sufficient for the job? Also when connecting both the lights together do they go to the same connector on the relay or seperate ones. If they go together can I just use one of those male/female conectors and slot them both together at the relay.

It is something which I feel I should be able to do myself and I did put some spotties on another car 10 years ago but didn't use a relay they worked fine but I would rather do it properly this time.

What alse should I look out for when fiddling around? If it is all too hard I might make a trip to my auto sparky tommorrow, just depends on my patience I guess.

cheers in advance,

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Reply By: KG - Thursday, Aug 14, 2003 at 19:22

Thursday, Aug 14, 2003 at 19:22
Hey Charlie,

I just put some lightforce 240's on my hilux....
I'm no electrician so I got a mate who was to rough it out for me and then I went away and ran all the cables nicely (with heatshrink, etc - all the time consuming stuff) myself.
so I can't help you on what plugs in where (my relay has a circuit diagram on it - no numbers)...
couple of words of warning... I initially used a 20amp inline fuse holder (all i could get from supercheap @ 4:30pm on a friday) i used the lights for a few hours over the weekend and came home to find the inline fuse holder melted to the point that i couldnt get the fuse out (to it's credit it was still working)... I have since replaced this with a 30 amp blade type waterproof fuse and had no problems...
While washing the car down that weekend I managed to fill the relay up with water and completely bugger it.
get the biggest, baddest fuse holder you can (within reason)
buy and carry 2 relays (same type) so if you kill one you can swap it over without trying to work out what plugs in where.
mount the fuse holder the right way up and try and avoid it with the high pressure hose :)
and finally... before you go running switch wires through the firewall check for existing accessory circuits (my povvo pack hilux had a heap of sr5 switch wires already run).


AnswerID: 27930

Reply By: Kev - (Cairns,QLD) - Thursday, Aug 14, 2003 at 20:13

Thursday, Aug 14, 2003 at 20:13
Yes you should run them through a relay as you dont want to run high current loads through the cab to the switches ect and to reduce voltage drop.
The relay also enables the use of the hi-beam cut out switching required by law.

Most relays have a circuit diagram on the side that corespond with the terminal numbers, why they didn't label them 1,2,3,4 ill never know !
Some don't so you will have to guess and try it out, place 12v and earth across 2 terminals (cannot dammage it) untill you hear a click. This will be your coil side for the hi-beam/cut out switch.
The other two are for the heavy wiring from the battery to the spotties.

BTW- you can loop the two spotties together instead of running the two cables back to the relay for joining.

Hope this helps.

AnswerID: 27939

Reply By: Truckster (Vic) - Thursday, Aug 14, 2003 at 20:46

Thursday, Aug 14, 2003 at 20:46
Remember to be legal or was the way, spotlights have to have on/off switch, and be activated via the high beam...

Dont ask why it needs both...
AnswerID: 27945

Reply By: donc - Thursday, Aug 14, 2003 at 21:57

Thursday, Aug 14, 2003 at 21:57
charlie, the following is the wiring up the relay and which bit should go to which number pin

wire from the battery to the relay should go to pin 30

power wires from the relay out to the lights go to 87 and 87a (one light per pin)

earth wire from chassis to relay goes to pin 85

power wire from on/off switch to relay goes to pin 86

hope this helps you sort some of the confusion out

cheers and good luck Don
AnswerID: 27957

Follow Up By: Tuco69 - Friday, Aug 15, 2003 at 08:14

Friday, Aug 15, 2003 at 08:14
Donc - Charlie hasn't mentioned the type of relay in his post. Depending on the type - some have 87 and 87a in parallel, while change over relays use the switching coil to output from one OR the other. On change over relays usually if the relay is not energised then the battery (30) is coupled to 87a. Once energised then the battery (30) is coupled to 87.
Usually the relay has a small schematic of its workings marked on it.
However it would be easy for someone who is not familiar with relays to pick up the wrong type.
FollowupID: 19340

Reply By: charlie - Friday, Aug 15, 2003 at 09:32

Friday, Aug 15, 2003 at 09:32
Thanks guys this has helped a lot I think I'll be able to get them running now with your advice and via the diagrams on the relay. Much apreciated.

AnswerID: 27991

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