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Hazard switch wiring weirdness


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As part of my rewire, I have a relocated carling hazard switch going in the centre console. I had the switch before, so I know this all works OK. 

Everything is wired up as it should be. I've double and triple checked the diagrams. I've also taken a feed from the 'flash' wire up to the hazard warning light on the dash. 

With the ignition off, the hazard lights work as they should. With the ignition on, the hazard lights and the indicators all work properly, however with ignition on and hazard / indicators off the relay is clicking away really quickly, the warning light on the dash flashes in correspondence and none of the lights do. 

I've tried a new relay, no change, and I know the switch worked fine previously. I've triple checked the wiring and all seems good. 

Can't figure out what's going on. Any thoughts? 

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Check the earths. I've had similar on the series, with standard hazards. Also check the terminals on the hazard flasher relay, mine had corroded, weird things happened with the relay.

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Further testing has revealed its something to do with the tell tale light on the TD5 warning panel. If I disconnect this, the problem goes away. 

So what have I got wrong there then? I've taken a feed from the LGN wire up to pin 9 of the 20pin plug. 

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4 minutes ago, Mo Murphy said:

Aren't TD5 warning lights earth switched ?

Mo

Some are earth some are live. 

 

10 minutes ago, Gazzar said:

How is the tell tale earthed? Or is it ECU driven?

Through the warning light panel, no ecu required. 

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8 minutes ago, Mo Murphy said:

https://images.app.goo.gl/qZGVqPkrNY68oMNi9

Don't know if this is any good ?

Mo

That's how the switch is wired, but no mention on there of connecting up the TD5 tell tale. 

14 minutes ago, Gazzar said:

Yes, so, is that feeding the relay? Plus -- bulb -- relay -- earth?

It must be I guess. Not sure how to go about fixing it tho. 

2 minutes ago, Gazzar said:

If the pin 8 is disconnected, it works normally? 

Pin 9, TD5 tell tale, but yes. 

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The relay is fed from the hazard switch. I've been through and tested all of the wires at the relay and where they go for end to end continuity and leakage to other earth / lives. All come up good. I've even simplified the switch by jumping the purple (perm live) and light green (feed to relay) and the dash tell tale still goes mad. 

However, as there is a tell tale on the switch itself, I don't actually need the one on the dash to work to be legal, it would just be nice to use it seeing as it's there. 

So for now I've removed pin 9 and put some heat shrink around it. If anyone has encountered and solved this problem with a TD5 dash upgrade in the past, please do share! 

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Yes that is how I have wired up the switch. The feed for the tell tale is taken from the LGN wire as the carling switch doesn't have the BR the stock switch does. It works just fine when you turn it on, but goes a bit nuts when turned off. 

The lights on the TD5 panel are a mix of live and earth switched. The hazard is live switched. 

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Mud UK were very helpful, but didn't have an answer. 

I solved it tho. There is no pin out on a carling hazard switch for an external tell tale, so don't try. Instead, use a relay. 

DSC_2378.thumb.JPG.00a4a9d3aec0987a2ea2f45b9a72c601.JPG

So the hazard light on pin 87 will only be lit when both indicator tell tales are live, which of course only happens when the hazard lights are on. 

So simple, I came up with it all on my own. 😁

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3 hours ago, daveturnbull said:

Mud UK were very helpful, but didn't have an answer. 

I solved it tho. There is no pin out on a carling hazard switch for an external tell tale, so don't try. Instead, use a relay. 

DSC_2378.thumb.JPG.00a4a9d3aec0987a2ea2f45b9a72c601.JPG

So the hazard light on pin 87 will only be lit when both indicator tell tales are live, which of course only happens when the hazard lights are on. 

So simple, I came up with it all on my own. 😁

I am not sure how that is working, surely the simplist way would be to feed the tell tale dash light direct from the indicator supplies with diodes inline.

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