Evening Gents,
Went to Maplins for standard 12 v 30amp 4 pin relays, when I got home I looked at them and found they were 5 pin. Now my understanding of electrickery is a little tenuous but thanks to Snowy and his ''How to rewire your car the easy way'' and several other posts on this excellent forum I feel confidant in giving it a go, I was planning on using 4 pin relays for my dip and main beam lights, I have got a Sierra column with switched earth stalks and was going to follow Snowy-es drawings as they are straight forward. I do not doubt there are ways to use 5 pin relays but for me I think the KIS principal applies. Can someone let me know if I can ignore the fifth terminal and use them as 4 pin. Sorry to be long winded.
Thanks, Pete.

The answer is yes. You can ignore the 5th pin (87A). That pin has the opposite function of pin 87.

Thanks Quinten, That is a relief.

Just ignore the pin BUT INSULATE IT.

If your lights are off and the 87a pin hits an earth it will blow the fuse, confusing the hell out of you for months!.

Just stick a red spade connector over it or even better heat shink pinched shut on the open end.

No need to insulate it --- if it is in a relay socket.

I believe you can leave the 5th pin alone.

As above, fitting them into relay holders might be a good move as a means of protecting unused pins - IIRC the holders are cheap to buy and give a means of mounting the relays too.

Thanks Gents, I will make sure the fifth pin is insulated.

4 pin
2 are to power relay, two are for switch


5 pin
2 are to power rekay, three is for 2 way switch

If you wanted 4 pin, why not buy one, maplins and ebag sekk them, without knowing how you intend to wire it, it may or may not cause problems.

Thanks for your comment 02GF74, Maplins did not have the relays I wanted on display, I asked a staff member for what I wanted, he went to his stores and came back with 2 relays. Being the trusting person I am I did not look at them until I got home and as its a big deal for me to go back to town to either change them or get a refund and I wanted to use them straight away. is the lesson learn't don't trust people? or just a simple mistake?
Cheers, Pete.

It really isn't a problem. I bought a big bag of 5-pin relays and use them for everything. Just ignore the 5th pin if you don't need it! It really isn't worth any more interweb time!!
ETA|: A 5 pin relay could be better suited to your headlamp scenario to ensure you have either main or dipped lamps and nowt inbetween!

[Edited on 13/1/16 by owelly]

YES........
5 pin relays are the same as 4 pin relays but for one difference. it can cause something to be "on" when the relay is off.....electric aerials are a common application. when "on" the aerial rises.....when the power is "off" the relay changes to a different terminal and the aerial lowers....
if you done want the extra function.....ignore it.
pin 30 = supply for consumer to be switched...
pin 85 = switch "on" live supply
pin 86 = earth for above (pin 85)
pin 87 = consumer "ON" when relay activated..
pin 87a = consumer "ON" when relay at "rest" (change over relay....)

Thanks Snowy2 and thank you very much for your 'how to rewire a car -the easy way' it has been an enormous help.

Cheers, Pete.

glad you find it useful....it can look as tidy as you like. i am about to rewire another car from scratch as my project car is nearing the time for a loom.....
i just wanted folks to see how easy it is to do.

p.s. .....it's Dave. :-)
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