740 Hazard Relay - constantly on

[redtel35]

Morning all,

I have a strange thing happening on my 1990 740 estate. When I switch the ignition on, the hazard relay clicks away at a fast rate. It does this even with the engine running. All indicator bulbs are fine and both hazard lights and indicators work fine when operated.

I replaced the relay and it has made no difference.

Has anyone come across this before or have any ideas of where to start looking?

Thanks in advance

[Laird Scooby]

When using the indicators, does the clicking you can hear match the clicking of the indicators and/or hazards? If not, it's almost certainly not the hazard warning relay aka flasher relay as the same one is used for the indicators.

However, the seat belt warning relay makes a similar sound - you should have a warning light on the dash for the seat belt, if it's not flashing then chances are the bulb is either blown or missing.

If the noise persists after putting your seat belt on, pull the passenger seat belt over and click that into place as if the Invisible Man is your passenger. If that shuts it up, there's a problem with the occupancy switch in the passenger seat. It should stop as soon as you put your seat belt on though - no occupancy switch in the drivers seat, it's assumed if the engine is running, the driver is present.

[redtel35]

Thanks for that info, you were right. Problem solved.

I plugged the drivers seatbelt in and the relay clicking stopped. Weird that I'd never noticed the noise before.

Is the clicking normal and should it sound a chime or light up a warning bulb anywhere?

At least I now know that I don't have to start fault finding the electrics.

Terry

[Laird Scooby]

Originally Posted by redtel35

Is the clicking normal and should it sound a chime or light up a warning bulb anywhere?


Terry

Only in the USA Terry!

For the UK, the clicking is 100% normal as well as the seatbelt light flashing on the dash/instrument cluster. It's only in the USA that they have a chime/buzzer to draw attention to it.

Glad it's sorted anyway, many strange, unexpected faults are down to the relays coming loose, the clips are meant to hold them in but frequently allow just enough movement to disconnect one or more of the relay pins - that's the drawback of having a vertical relay board and also fuse board.

[redtel35]

Thanks Dave!

I've no flashing light on the cluster, but, I am just going through the lights in any case. I've now got most of them working.

Terry

[Laird Scooby]

Originally Posted by redtel35

Thanks Dave!

I've no flashing light on the cluster, but, I am just going through the lights in any case. I've now got most of them working.

Terry

You can see where the seatbelt light is in this pic Terry, obviously caught when it was lit!



You should also have a lamp test function which will bring almost all of the warning lamps on in the bottom row when you first turn the key to position 2, they should go out when the alternator starts charging.