Relay problem

[jeff]

2010GSA

Have had an unusual problem with a relay.

Bit of background information.

All my accessories (louder horns, garmin, socket outlet for heated vest etc)
are connected to a "Fuze Block"so no canbus problems
Everything has worked properly for over three years.

couple nights ago horn not working. checked fuse (20amp) blown. Replaced fuse which blew immediately.

Process of elimination showed no problem with any of wiring and that the problem lay in the relay itself.

Standard four post relay wired according to manufacturer's diagram (and normal practice)

horn push to 85
solenoid ground to 86
(using bike's horn push)
12volt supply from fuze block to 30
load (to horns) 87

Checking relay with meter shows a direct short to earth caused by some failure in the relay which has
resulted in a permanent circuit between terminal 30 (12v supply) and terminal 86 (solenoid switch ground.

Before I try to open up the relay to see what has happened out of curiosity, anyone any idea what has happened.

Have had relays fail before but usually this is a solenoid switch malfunction

Replaced relay with same make spare, everything working fine.

 

[Nick V]

Checking relay with meter shows a direct short to earth caused by some failure in the relay which has
resulted in a permanent circuit between terminal 30 (12v supply) and terminal 86 (solenoid switch ground.

Before I try to open up the relay to see what has happened out of curiosity, anyone any idea what has happened.

Have had relays fail before but usually this is a solenoid switch malfunction

When opening up the failed relay, I would check for any loose pieces of metal floating about which may have caused a short.

I once had a 30A 4-pin relay fail after two year's worth of usage as a starter motor relay on my K1200S streetfighter. Pretty good innings, considering the load the thing had been asked to carry! The high-amperage switch contact had become brittle through continual overheating/cooling, and eventually just sheared off.

 

[Tusky]

I would just replace the relay..... Not worth a patch and repair job IMO

But like you I am always curious to find out what has stuck, broken or welded itself.

 

[Pukmeister]

I've no idea of the total number of relays, contactors and overloads I've replaced over the years in industry but its a lot. The things work hard for a living, repeatedly carrying power and being hit by inrush current surges. Sometimes they fail quickly, sometimes they last. No logic or pattern to it, just replace and see if it lasts better than another 3 years.

 

[Bendy toy]

Have you tested the horn directly to the battery?

 

[jeff]

Have you tested the horn directly to the battery?

Yes.part of process of elimination. Replaced relay all fine.

Took failed relay apart.

Solenoid works ok but direct short from 30 to earth. Comparison with new one showed that a small electronic bit (resistor?) has been destroyed/burnt out. It is not a diode.

However, replacement working fine. Sod's law was that every tourist seemed to be pulling out from side roads looking wrong way when horn not working.

 

[Fanum]

I've still got loads of these from when I used to fit stuff to commercial washing machines and dishwashers

of various types, voltages and pinouts.

Quite interesting being able to see the gubbins doing its stuff

 

[Nick V]

Quite interesting being able to see the gubbins doing its stuff

Useful for visual fault diagnosis, too!
Very interesting that there seem to be no construction and use regulations for these to be fitted to motor vehicles...