Hazard lights

C

Chiefmechanic

Active Member
My a2 has just failed mot for hazard lights not working. This is my first mot with this car a 1.4 tdi bhc engine 2004.
It had a Towbar fitted by the previous owner but has been removed prior to my buying it.
hazard lights will not come on with or without ignition on. There seems to be no power to the switch with the ignition off. When the ignition is on the backlight of the switch lights up as it should.
I have changed both the switch and the relay. Fuse 7 is good And the only anomaly is the hazard switch flashes in time with the right indicator but not the left.
parking lights work as they should.
any help appreciated.
brian.
 
Chiefmechanic said:
My a2 has just failed mot for hazard lights not working. This is my first mot with this car a 1.4 tdi bhc engine 2004.
It had a Towbar fitted by the previous owner but has been removed prior to my buying it.
hazard lights will not come on with or without ignition on. There seems to be no power to the switch with the ignition off. When the ignition is on the backlight of the switch lights up as it should.
I have changed both the switch and the relay. Fuse 7 is good And the only anomaly is the hazard switch flashes in time with the right indicator but not the left.
parking lights work as they should.
any help appreciated.
brian.
Click to expand...
Worth a look underneath the rear, to look for the tow bar socket which would have been there. I'd guess your problem is associated with the tow bar electrics fitting or removal.
Mac.
 
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steve_c said:
I'd say this sounds like a job for @timmus but I don't know how often he gets across to Antrim.
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I do occasionally visit Antrim, because my aunt lives there, but I have no plans to visit the island of Ireland until late October.
Hopefully my presence won’t be necessary in this case.

Brian, could you please check Fuse 34? Check and double-check. If necessary, try a different fuse, as sometimes fuses pass a visual check when they are in fact blown.

Cheers,

Tom
 
Got my mate to check fuse 34. There was no fuse in that slot and when one was put in there was no difference. As the hazard lights are supposed to work wether or not there is a key in the ignition then the switch must get power from somewhere that is not ignition controlled. Any ideas where this power comes from.
 
More than likely caused by the tow bar electrics being bodged. Find the wiring and make sure it is completely disconnect and insulated.
 
Chiefmechanic said:
Got my mate to check fuse 34. There was no fuse in that slot and when one was put in there was no difference. As the hazard lights are supposed to work wether or not there is a key in the ignition then the switch must get power from somewhere that is not ignition controlled. Any ideas where this power comes from.
Click to expand...
Check out the wiring diagram for details on the connections to the hazard switch.
 
I would agree that the wiring of the Towbar by someone previously has created a fault. The Towbar wires are all disconnected. The fault I believe is that there is no power to the hazard light switch. The indicators and parking lights Work as they should apart from the right indicator flashing the hazard switch.
I believe there should be power at the hazard switch with no key in the ignition but I can’t find where this power should be coming from.
 
Fuse 7 and its wiring provides the hazard power. Are you getting power at fuse 7, if so then check the wiring to the switch.
 
And on the hazard switch itself, there is a live feed (black / blue wire) from fuse 38. Not sure if this activates the relay, just the switch light or both

Cheers Spike
 
Not gettin anywhere with the hazard lights. Changed the hazard switch, flasher unit and cccu all to no avail. Set the alarm off and the sounder goes off but no hazard lights. Removed any wires left over from the Towbar fit.
Apart from the hazard lights not working the only anomaly I have is the hazard switch flash on a right turn indicator. I think the issue is that I don’t have any power to the hazard light switch but I can’t find where it comes from. I have downloaded a manual for the a2 but so far in the 555 pages of wiring diagrams I can’t find this information. Any help appreciated.
 
Still fuses 7 and 38 are the 2 power sources. I would be having a good look around to see if anything aftermarket has been added to the wiring as this could be the source of the problem. Also check for damaged wiring NEAR where the bodged towbar electrics were fitted. Standard bulbs fitted everywhere I take it?
 
Chiefmechanic said:
Not gettin anywhere with the hazard lights. Changed the hazard switch, flasher unit and cccu all to no avail. Set the alarm off and the sounder goes off but no hazard lights. Removed any wires left over from the Towbar fit.
Apart from the hazard lights not working the only anomaly I have is the hazard switch flash on a right turn indicator. I think the issue is that I don’t have any power to the hazard light switch but I can’t find where it comes from. I have downloaded a manual for the a2 but so far in the 555 pages of wiring diagrams I can’t find this information. Any help appreciated.
Click to expand...
Best to open the file as a pdf, then you can search on 'Hazard' for example which gives a number of hits, eg page 20, 53 etc.
On page 20 the switch (E3) is shown and if you follow the references, pin 1 is the supply from fuse 38. Check this please.
 
There is no power to pin 1 on the hazard switch with the ignition off.
when I switch on the ignition I have power to the hazard switch at pin 1.
If I put power to pin 1 with the ignition off then the dash lights all light up as if I had turned the ignition on.
There is no power to fuse 38 at any time. I put power to it and I got an engine management light but no hazard lights.
I have changed the immobiliser horn and it made no difference. I am stuck to find anything else to change.
 
Chiefmechanic said:
There is no power to pin 1 on the hazard switch with the ignition off.
when I switch on the ignition I have power to the hazard switch at pin 1.
If I put power to pin 1 with the ignition off then the dash lights all light up as if I had turned the ignition on.
There is no power to fuse 38 at any time. I put power to it and I got an engine management light but no hazard lights.
I have changed the immobiliser horn and it made no difference. I am stuck to find anything else to change.
Click to expand...
Sorry, try pin 6 on the hazard light switch, I think this should be the permanent supply which is fed from the hazard light relay.
The hazard light relay appears to receive its supply (pin 6/ZV) from the Central Convenience Module (pin 3/11).
 
I have bypassed the switch by shorting pin 4 and 6 on the switch and still no hazard lights.
no power at pin 6 with ignition off and 5volts with ignition on.
no power at pin 6 on the plug into the hazard light unit with ignition on or off
 
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