Help diagnosing Hazard light fault please

[J-D-Stagpump]

Hi all and thanks in advance for any help.
Firstly, I diagnosed a parasitic drain on my battery. when I pulled the highlighted fuse the drain went from 0.27 amps to 0.01 amps. Looking at the fuse layout on the panel it appears to be for the Hazard lights and the horn but while the hazards do stop working the horn remains functional I am a little confused as to why.

Secondly, if I am right and the hazard lights are to blame, do you have any advice on how to diagnose the problem??

Any help will be gratefully received.

I should have mentioned it is a R reg 97 MK3 Astra

[E-bmw]

On lots of cars the horn remains active when the ignition is off for safety reasons, but it will draw no current unless the horn is pressed.

If the horn circuit is drawing current when the button is not pressed you may have an issue with the horn relay.

If this is the case, hopefully changing the relay will help.

[SlimJim16v]

With the std old electric horns, it is possible for them to partially fail, so could be drawing some current without sounding.

Put a meter across the +ive and -ive terminal of the horn with it disconnect/off the car to measure the resistance. It should be zero ohms, or open circuit.

[freddytin]

Have you tried removing / disconnecting the hazard light switch...Quite common for them to fail.

[geeks]

If i read the OP right then with the fuse removed the hazards no longer operate but the horn does.

So with that in mind it is possible the fuse is for the alarm power sounder (if you have one of course, my old vauxhall did)

As to the cause of your voltage drain. Indicator relay or hazard switch. Put the fuse back in and remove the hazard switch and see if the volt drop remains. If not then there is your culprit, if it does then just move forward through the chain.

[Penelope Stopit]

Thats a 3 Watt drain
Check the boot light is going off when the lid is closed
Check glove box light but I think thats on ignition
Check has it an add-on alarm with battery backup, battery could be faulty and draining it
Has a radio been wired the wrong way, wires yellow/red Wrong way round

Any of the above could be wired to the hazard fuse

[LarJammer]

I would expect an alarm to be wired into the hazard circuit, any evidence of any aftermarket wiring?

[E-bmw]

SlimJim16v said:

It should be zero ohms, or open circuit.

I think you will find zero ohms is a short circuit!

[SlimJim16v]

E-bmw said:

I think you will find zero ohms is a short circuit!

Doh