Puddle lights - help with my relays please

Electrical 206CC problems
George 206cc
Posts: 52
Joined: Fri Jun 16, 2017 9:27 pm

Puddle lights - help with my relays please

Post by George 206cc »

Hello all

I'm trying to fit my car with puddle lights. I'm going to use some blue led strips off eBay. I've used them before in other places and they work great.

I took the door card off, 6 wires going to the door handle/lock mechanism. The green wire which goes from the car to the door mechanism to ground, has 3V in it when the door is closed. 3V isn't enough to run my blue LEDs so I'm going to use relays.

I bought 2 (one for each door) relays. 12V, 40A, 4-pin, mini relays, normally open (NO) contacts, with diodes so as to not damage the central locking circuit (I read that's a thing). Yes, I should have bought Normally Closed (NC) contacts so the circuit will be closed when the current is 0 when the door is open, but let's skip over that for now...

Thing is, I can't seem to get the relays to close the high(er) current circuit, door open or closed and I can't work out why!

I have the green wire to relay terminal 86, 85 to ground. I have 12V from battery to terminal 30, 87 to my LEDs. It seems whether I have current in the green wire or not (across the coil 86,85) the relays just will not close the circuit of 30,87 and I cannot work out why!

Does anyone have any ideas? I can provide more detail if you ask questions. Please help!

Thanks in advance, George

IanL
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Location: Jersey, Channel Islands

Re: Puddle lights - help with my relays please

Post by IanL »

At a guess, the 3V is semiconductor logic with very little current supply capability. Your relay coil is probably dragging it down to virtually nothing. You could confirm that by measuring across the coil terminals with the door closed.

Even if that is not the case, that 3V is probably always live, to enable the alarm system. Putting an extra load on it will drain the battery with the engine off, which is undesirable.

I suggest you fit an old-fashioned independent door switch and wire it with 12V from a fused supply to control the relay, or just straight to the LED. As a bonus, that will cause no drain on the battery unless the door is open.

George 206cc
Posts: 52
Joined: Fri Jun 16, 2017 9:27 pm

Re: Puddle lights - help with my relays please

Post by George 206cc »

Thanks for your reply. Sounds like I won't be needing the relays if I'll be using an old-fashioned independent door switch instead then. How would I make that? Have 12V from the battery go to the door switch terminals along with the other 6 wires that plug in and the door switch itself be the switch instead of the relay? Not sure how to approach getting an additional independent door switch. Maybe send me a link to something I could buy and how I could wire it?

IanL
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Re: Puddle lights - help with my relays please

Post by IanL »

Do an eBay search for "courtesy light switch". Huge selection. The usual site for installation is the front door pillar (the part to which the hinges are attached).

You can take the fused 12V supply direct to the LED +ve terminal, and connect the -ve terminal through the switch to earth. No need to interface to the door lock wiring at all. When the door is opened, the switch contacts close and the light comes on. The earth connection is often part of the switch.

George 206cc
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Joined: Fri Jun 16, 2017 9:27 pm

Re: Puddle lights - help with my relays please

Post by George 206cc »

That's interesting.

The only ones I can find on eBay and other electricals sites are the telescopic/plunger type / push switch. Can't quite imagine how I'd mount it at the front door pillar. Raining at the moment but will go and have a look when dry. It looks like I connect the earth wire from the LEDs to the switch, then the switch goes to ground just by the screw that screws into the body/pillar. Does this mean I'd have to drill and tap my own hole?

IanL
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Re: Puddle lights - help with my relays please

Post by IanL »

George 206cc wrote:...Does this mean I'd have to drill and tap my own hole?
Yes, unless you use a self-tapping screw, in which case just drill.

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gazza82
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Location: Buckinghamshire, UK

Re: Puddle lights - help with my relays please

Post by gazza82 »

Or take a feed off the internal light? Run down one a pillar to a relay then that feeds the lights.
Family Fleet: ex-Cayman Green 206 CC 2.0 LE, Indigo Blue 206 1.4 HDi Hatchback, Subaru BRZ Auto, Alfa Romeo MiTo

George 206cc
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Joined: Fri Jun 16, 2017 9:27 pm

Re: Puddle lights - help with my relays please

Post by George 206cc »

Gazza I don't want to do that because I don't want the passenger door light on when I open only the driver's door, or the other way round. Even if it can't be seen, it's the principle, you know?

George 206cc
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Joined: Fri Jun 16, 2017 9:27 pm

Re: Puddle lights - help with my relays please

Post by George 206cc »

IanL wrote:Yes, unless you use a self-tapping screw, in which case just drill.
Okay, thanks. I'll have a think. Can't immediately see where I'd put the switch but I'll figure something out

George 206cc
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Joined: Fri Jun 16, 2017 9:27 pm

Re: Puddle lights - help with my relays please

Post by George 206cc »

Right, I've figured out how I'm going to do it. Ordered a few bits. Will try and have it all done by the end of this week and will post on here how it goes.

George 206cc
Posts: 52
Joined: Fri Jun 16, 2017 9:27 pm

Re: Puddle lights - help with my relays please

Post by George 206cc »

Done! I wired it all up, drilled all the holes, it works really nicely. I used the 'metal bodied switch' from 12voltplanet. I placed them on the front door pillars close to the rubber casings for the wire looms. Very pleased

IanL
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Re: Puddle lights - help with my relays please

Post by IanL »

Nice one :thumbs: