Sorry, should have been more specific. On my relay, which contacts are 85, 86, 87, and 30? They aren't marked up and the wiring diagram in the link isn't labeled either.

The same connections whether you have the 1C or 2NO relay

Brilliant! Nice one!

Ok, I've plugged in as above. Whether the low beam switch is on or off I always have continuity between 30 (input) and 87a. So is my relay knackered?

thunderace wrote:85 to earth
86 to the switch
87 to the headlights
30 to the battery (via 15A fuse for twin headlights)

Do you still need a relay? I can get one posted out tomorrow.

I'll have one please mate...might as well sort mine out - want to run a 100w rally H4 lamp in my single headlight...

CMSMJ1 wrote:

thunderace wrote:want to run a 100w rally H4 lamp in my single headlight...

Is the rest of your wiring standard to do that?

spongy.bob wrote:

CMSMJ1 wrote:

thunderace wrote:want to run a 100w rally H4 lamp in my single headlight...

Is the rest of your wiring standard to do that?

No idea! Though I expect with a single lamp the draw will be the same?

Electrics is voodoo...

If you're using a relay the high current passes direct from battery to headlight through the relay. The wiring should cope fine as the JDM spec bulb has a 55w (or is it 60w?) main beam and all wires are the same spec.

spongy.bob wrote:Ok, I've plugged in as above. Whether the low beam switch is on or off I always have continuity between 30 (input) and 87a. So is my relay knackered?

I thought the relay pins weren't marked?

If you've connected as I've drawn, with the switch OFF you should get an open circuit reading (1.) on the multimeter between the battery and headlight connections. With the switch ON the reading should change to a low resistance.

If you've already wired up you can check as follows:

Disconnect the bulb and put your red multimeter probe into the top connector on the plug (56b)


Place the black multimeter probe on the battery negative terminal.

With the ignition and lights OFF you should get a 0v reading.

With the ignition ON and lights OFF you should get a 0v reading.

With the ignition ON and lights ON dipped beam you should get a 12v (approx) reading.

With the ignition ON and main beam lights ON (***not the flasher switch, the proper low or high beam switch) you should get a 0v reading.

***The flasher switch does not switch the low beam off but the high/low beam switch does.




Let me know your results

CMSMJ1 wrote:

thunderace wrote:85 to earth
86 to the switch
87 to the headlights
30 to the battery (via 15A fuse for twin headlights)

Do you still need a relay? I can get one posted out tomorrow.

I'll have one please mate...might as well sort mine out - want to run a 100w rally H4 lamp in my single headlight...

I'll post one out to you Tuesday, no point doing any posting this side of Easter. Still got your address

Cool - appreciated mate. Also, more electrickery info in this thread as to how it works is good!