autoswitch/PIAA relay help please

[monkeyboy]

I was wondering if I could ask some advice please. I'm putting in an autoswitch - that looks straightforward enough except... the lights are PIAA 510s and have a weird piaa relay and wiring. I'm not good at wiring but I usually understand it after a while. But a while has expired in my case and I still can't work it out.

Autoswitch power, earth and signal I understand fine. They then enable power through the purple and black wires that would trigger the relay circuit and turn the lights on - no problemo

It's how to cut into the PIAA circuit that I'm having problems with. There is a 3 pin connector - 2 whites and a black. The black does nothing as far as I can work out even though it is live (the led on the switch has never worked if it's to do with that). If I arc between the 2 white wires (one has power from the relay, the other goes to earth) then the lights come on. The handlebar switch just completes the earth. I understand that but i don't understand how the relay provides permanent power to the handlebar switch yet still switches in the main circuit when it's earthed - maybe it's my misunderstanding but I thought a normal relay connects internally when earthed - ie I didn't think you'd get live power out the other side of the relay before it was earthed. My electrics knowledge is BASIC!

Anyway the autoswitch instructions seem to say I should tap the positive purple wire from the autoswitch to the outside white wire (the power from the PIAA relay trying to get to earth) but I can't see what difference that is going to make because there is power on that wire anyway. That isn't going to earth the power which is what is required for the PIAA relay to complete, or is it through the autoswitch earth?

Does anyone know how to tap into this PIAA circuit please? It looks to me like I need to just use the autoswitch as a dumb unpowered switch to complete the PIAA circuit, or else I have to tap into other wires in the PIAA relay but I just can't work out how! All this black and white American wiring just throws me I'm sure it's simple! I was trying to find an online diagram of the PIAA circuit to try and understand that but I can't find one.

I'm just confused!

 

[essjay]

I could be completely wrong about this but from looking at my (yet to mount) 510's are you sure that the two whites are not live while the black is ground?

I presumed that the black is the ground for the LED in the switch while one of the whites is power into the switch while the other white is power coming from the switch into the relay which should trigger the relay when the switch is flicked.

If you follow the black wire all the way back it seems to be wired in with the other ground wires.

 

[monkeyboy]

I could be completely wrong about this but from looking at my (yet to mount) 510's are you sure that the two whites are not live while the black is ground?

I presumed that the black is the ground for the LED in the switch while one of the whites is power into the switch while the other white is power coming from the switch into the relay which should trigger the relay when the switch is flicked.

If you follow the black wire all the way back it seems to be wired in with the other ground wires.

Nope. - One of the whites is connected to the battery earth. I've had them working with the handlebar switch for a while but want to move to the autoswitch cos they kill the battery in 5 minutes if left on.

I've checked out all the pins with the circuit tester. Black is live, the outer white is live and the middle white is earth. It's just weird to me! If you have a look at the wires into the relay it looks weird as they send blacks (live from the battery) off to the lights then the whites come back from the lights and go through the relay to earth. That what my (numpty) analysis has given me.

Oh POOOOOO. Could it be that I have the whole lot back to front? I've got the blacks on the +ve terminal and the whites on the -ve. I bet that's where I've gone wrong and why the led on the switch has never worked. DOH! What a TOSSER. That would make sense then I guess that the autoswitch would put power into the PIAA relay and mimic the closing of the handlebar switch. Double DOH!

So - are the blacks ground wires in the US?

 

[monkeyboy]

Balls - 50/50 chance and I obviously got it wrong Swapped whites onto the +ve and the lights work. Still no LED on the switch but who cares. Putting positive from the battery to the outside white wire to the relay turns them on - so I just cut the purple positive from the autoswitch into that and it should all work as advertised. What a knob

 

[essjay]

I usually always presume that a black wire is ground. That said, ground can be any colour but if I come across something with a black wire I presume ground.

The thing that figured it for me when I was looking was the two whites and a black into the switch. I knew I had to have a power into the switch and a power out to the relay that would be live once the switch was on. Since there was two whites I guessed one was power in and the other switched power out. The black wire then being the ground that the LED would require.

Like I said I could have it wrong.

But as you said above, if you find the wire that switched the relay (you mention the outside white) and then connect that to the switched output of the autoswitch you should be fine.

Me, I'm going to connect that wire (outside white) to the power from my high beam so the 510's come on with the headlight. The 510's I have are spots so I want them on with the headlight. If I had a separate switch I'd forget to turn them on. With the fogs I'm just going to wire straight into fusebox.

 

[monkeyboy]

Cheers. I just looked at the connections at thought WTF! It all makes sence now. My 510's are spots too but I use them for dipped assistance. They're adjusted low but still do a fantastic job of spilling light up to make the dipped beam very good. I could put on with dipped but I'm not sure they'd pass mot and I want them switched with the key rather than always live as now.

Thanks for your help. Those 510s are brilliant and they look the dogs too

mb

 

[essjay]

No worries. I need to get mine mounted soon - they've been in the shed for months.