Relays

[nelmo]

I'm no expert on relays but my indicator flasher relay seems to have died this morning - my indicator dash light comes on but does not flash and the relay is making a buzzing noise.

 

Sounds terminal to me but are relays affected by cold? It was just about freezing this morning - is it possibly going to start working when the temperature rises?

 

[jaimo]

Sometimes relay stick give them a tap

[nelmo]

I was wondering about that but aren't all modern relays solid-state? Mine are only a couple of years old...

[theduck]

I was wondering about that but aren't all modern relays solid-state? Mine are only a couple of years old...

Nope, most automotive relays are good old fashioned proper mechanical ones.

[fry61]

Was the battery good enough to start the car? If so check the earthing/power feed to the relay. As above a continuous buzz from a relay indicates its not got sufficient current to close the circuit, don't leave it buzzing as the relay coil draws more current when the magnetic circuit is in-complete.

[nelmo]

Hmmm, could it be a problem if it is on too long?

 

I don't have column stalks, my indicator is a manual switch on my dash (no auto-cancelling). On my way to work this morning, after one turn, I forgot to switch the indicator off for about 2 miles (yeah, I know, one of those people ) and it was after that I noticed it wasn't flashing (I can't be sure if it was before - I think it was).

 

I'll try give it a whack later, although it's not easy to get to...

[nigelt]

Do the indicators actually come on? Depending on the electro-mechanical workings of the indicator circuit, it could just be one of the bulbs has blown and so does not have enough energy to energise the relay. Or you may have a short somewhere.

 

Nige

[nelmo]

Ahh, hadn't actually checked that - I was working on the belief that this would cause the indicators to flash even faster, which is what happens on a normal car but I'll check - thanks...

[nelmo]

So, I'm guessing a relay that rattles like a castanet is kaput, yeah?

 

And coincidentally, it's a Cargo relay (surely the most ironic product name ever), same as my alternator that died a few weeks ago. Guess which manufacturer I'll be avoiding for, like, forever?!

[nelmo]

Is it a relay or the flasher thats buzzing gone?.

It's just one unit, isn't it? This is a pic of the inside - you can see the capacitor has dropped off which was the rattle:

 

Edited February 13, 2018 by nelmo

[fry61]

The capacitor is probably in circuit to damp the spark across the main contacts --- without it being in its correct place ( electrical place -- the contacts are probably burnt & causing a high resistance & no glow of lamps, Its a very unusual fault though, all the relays in our car are from the donor.

[nigelt]

That's more likely to be the timing capacitor. They don't usually use electrolytic capacitors to supress sparks.

There is a white stripe down one side of the capacitor, that's the negative side, if you are soldering it back in.

 

Nige

[nelmo]

Thanks for that but, apart from the fact that my soldering skills are sorely lacking, I had to cut the unit open to get to the inside for that pic.

 

Also, there has been some arcing going on because the side of the relay unit shows signs of melting, probably when I was running it after the capacitor dropped off.

 

Bottom line - it is one very dead relay/flasher unit - new one on order...