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Discussion Starter · #1 ·
Okay, so the hazard warning lights haven't been working for the past year (too long, I know), but as MOT is due in a week or so, I thought it's about time for that to be sorted. What happened every time you turn on the hazard warning flashers every time throughout the past year was a whole lot of buzzing! I worked out that the relay is dead and that it was the buzzing source, so I went out to find a replacement.

Found the whole right (is that left on your cars? the one that controls the lights?) handle-switch together with the relay which was allegedly tested just before it was taken off the previous Mondeo it was on. Got home, replaced my whole right handle-switch with that one, turned on the hazard warning flashers and BUZZZZZ! I was about to smash my head into the steering wheel, but then it started working. Got out, checked all flashers, all were working. Great, I thought, it just needed to warm up after sitting for years. Turned the hazard warning lights off and back on and surprise, surprise - BUZZZZZZ! Off, on, off, on... They again worked fine on 6th or 7th try and then there was buzzing every next time.

That was yesterday, today I found an old flashers relay in the garage that we saved of our old Taunus. It's two times longer than these, but it still fitted. The only difference was that this one said ...+0.5W, while the previous, original, two were ...+4W. So, turned on the hazard flashers - BUZZZ - shorter than it was on the first try yesterday and then it started working. Went out, checked all flashers, all was fine. Turned it off and back on - working fine! Tested left flashers, right flashers, lights, all fine. Hazard flashers on again - BUZZZZZZ... And it just buzzes ever since.

So, my question is...is my car killing these relays? :/ Or should I just go out and find another one (I would ask that guy for a replacement)?

All the time, with all three relays, the directional flashers were working just fine. There was no noise of any kind except for clicking when it was pointing left or right. All the fuses are fine. There seems to be electrical mailfunction, directional flashers don't work when the key is not in ignition position.

Anything else I could/should check?
Okay, so the first one was dead when we bought the car, have no idea for how long that was. Second one... It was half way dead when I bought it? And the third, old Taunus one, died because it was meant to be working on less power?


Have you guys experienced any dead flasher relays on your Mondeos? Three dead ones seem to be too much, as I couldn't find any posts regarding this issue
 

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Discussion Starter · #2 ·
Got the multimeter, relay out, hazard flashers on - the voltage is the one from the battery and the current is 0.09~0.15A.

Found the diagram in the manual, I guess I'll try to follow it through later today.

In the meantime... Anyone?
 

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Big Daddy
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A relay can make a buzzing sound like that when the current supplying it's coil is too low. I would guess that you have a bad connection somewhere that is limiting the current flow to the relay. Sounds like the relay is trying to energise, but in doing so it's supply voltage is dropping causing the relay to drop out. It will then repeat the same cycle again. This happens very fast and results in the buzzing noise you can hear. It's often called relay chatter.

How did you measure the voltage going to the relay? Did you measure it with the relay unplugged? If so you may well get a false reading. Without the load the coil in the relay generates, you may well measure 12v, but if there is a bad connection somewhere along that 12v feed, when you load it up the bad connection will limit the amount of current that circuit can supply the relay.

Ideally you need to read the voltage to the relay coil whilst it is plugged in and the hazards are switched on. My guess is that you will see the voltage fall down when you try to turn the hazards on and the relay is chattering.

So you are doing the right thing by tracing that circuit back, find out where the +v and the -v supply for that coil comes from. Somewhere along the line i think there will be a bad connection.

Good luck!
 
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