Hazard Switch & Indicators - fault diagnosis
Posted 12 April 2008 - 09:53 PM
The hazard switch and indicators often cause problems in defenders, most commonly the indicators stop working, but the fault is actually with the hazard light switch.
This post aims to explain how the hazard switch works, why it's malfunction stops the indicators working, and how to test for and diagnose the fault.
To get to the back of the hazard switch, remove the two screws and pull the switch panel out. you'll then see this.
The multi plug has 7 wires going into it, there's also the Black (red trace) and Black wires, which are connected directly to the switch body. these are for the indicator in the switch itself.
Black(red) - indicator supply
Black - earth
Remove the multiplug, you will then see the two sets of pins, x3 and x4, top and bottom (as viewed in the photo, not as mounted in the dash).
The top set are concerned with powering the flasher unit, the bottom set dictate what the flasher unit actually lights.
This picture shows the 4 wires that connect to the bottom set of pins
And this picture shows the 3 wires that connect to the top
To make things easier to see, here is a schematic of the switch.
With the Hazard switch in the 'off' position
'Suppy to flasher' is connected to 'Light switch supply' - which comes on with the second click of the ignition switch
With the Hazard switch in the 'on' position
'Suppy to flasher' is connected to 'Permanent Supply' - 12vDC
*Flash* is connected to 'Left Indicators', 'Right Indicators', and the 'Switch tell-tale'
What this means is, if the switch is faulty, the flasher unit doesn't get a power supply, so it can't flash the indicators via the indicator switch on the column.
You can test the switch using a multimeter (continuity or resistance), or test lamp. You can also test the vehicle wiring as follows.
You will need a fused piece of wire (or test lamp), you don't want to risk a dead short if you get it wrong.
This is what i made to test the wiring, the lowest value fuse i had was 5A.
If you link 'permanent supply' (purple) to 'Left indicators' or 'Right indicators' the indicators on that side should light, constantly though, not flashing. this proves the bulb wiring is ok and you have supply to the loom plug.
If you link 'permanent supply' (purple) to 'supply to flasher' (light geen), the indicator stalk switch should work the indicators as normal (flashing). The indicator switch is connecting *flash* to 'Left Indicator' or 'Right Indicator' - the wiring is duplicated at the stalk switch. If you want to make a seperate link wire you can replicate the stalk switch action at the loom plug as well.
You can repeat the two tests above, using 'Light switch supply' instead of 'permanent supply', the ignition switch will need to be on the second click.
'Switch tell-tale' is the live supply to the bulb in the switch housing, it is grounded by the seperate black wire connected to the switch body.
- Paddy likes this
Posted 20 January 2010 - 04:05 PM
S Reg 1998 130XD Pulse Battlefield Ambulance with a Brazilian 300Tdi....
Africa done, South and Central America done, North America done, Canada done, Alaska done,,,,HOME.
Posted 21 January 2010 - 12:16 AM
Fifty Shades of Pennine grey
Posted 28 February 2010 - 06:57 PM
Posted 08 July 2010 - 11:58 AM
For info, the wire shown as dark green here is white with a green trace in the TD5 defenders. Make sure this is not confused with the green with white trace wire.
Also for info, for a TD5 HZ switch, to get the little light in the button to illuminate you join the black/red wire with the orange/red wire.
My 86reg 90 with original loom, the dark green wire had a small white rubber band marker on, this attaches to the White with green trace wire as Kev says.
Posted 04 November 2010 - 07:38 AM
Posted 04 November 2010 - 08:13 AM
Posted 04 November 2010 - 10:57 AM
Do you have a multimeter or a test lamp?
If you have a spare length of wire or lamp you can test the wiring at the hazard switch connector, as described above.
Have you done this?
Posted 04 November 2010 - 01:53 PM
Posted 13 November 2010 - 08:40 PM
Posted 13 November 2010 - 08:56 PM
P.S a very helpful thread.
Posted 02 December 2010 - 04:46 PM
The clicking is not consistent as when the indicators are selected but instead erratic. If I turn my lights on it reduces the frequency of the clicking but it still does it occasionally.
I put the M.meter across the light green and earth on the flasher relay and it always has 13v across it (with engine running) as it ony happens with the IGN on. If I turn the lights on it drops to 12.8v and it reduces the frequency of the clicking.
I assumed this was due to a short cicuit so I pulled my landies wiring loom to pieces and sepreated all the wires but it still happens. I have checked all the indicator associated connections and cannot find a short there, so I am at a loss as to what else it could be.
The only theory I have left is because it only happens with the IGN on there is a fault with the hazard switch across the Green - Light green connections but I have checked this with the m.meter too and it appears to be fine too.
I have read the following article and all works fine.
BUT I CAN'T STOP THE CLICKING ITS DRIVING ME MAD!!
Does anyone else have any thoughts?
Posted 11 December 2010 - 09:45 AM
Since it only happens with the ingnition turned on then it leads me to believe the fault is IGN feed but I cannot find any shorts on this line and all voltages/currents are correct.
The only thing I can think maybe the problem is the trailer socket so Im going to disconnect that now and see if it cures it. Beyond that I am lost.
Posted 11 December 2010 - 11:34 AM
it maybe your relay has a problem.
Posted 12 December 2010 - 08:52 PM
Have drawn a circuit diagram which I'll upload later when on computer rather than iPhone. It may help someone else out in future.
Posted 12 December 2010 - 09:39 PM
Since it only happens with the ingnition turned on then it leads me to believe the fault is IGN feed
I doubt it. I suspect the ignition needs to be on to make the problem appear, but is not actually the cause of it.
Posted 13 December 2010 - 12:48 PM
Sorry, I don't think the IGN feed is the promblem but rather the problem is somewhere on the IGN feed.
As you can see from the diagram the flasher relay uses the same power feed to activate the relay and also power the bulbs which would imply that the flasher relay should click constantly as it always has power.
I know it is not as simple as this, I assume the other components in the flasher relay and Haz switch are there to prevent this. My understanding of electrics doesn't go as far as understanding how this actually works. Can anyone explain this?
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