New one on me. Car parked up and locked on my drive and suddenly it generates a loud continuous clicking noise.
This is with everything turned off and no key in the ignition.
I investigate under the bonnet, check relays etc and the noise seems to be from the vicinity of the ABS pump. Quite loud. Under the fuse box but difficult to pinpoint exactly, even with a mechanics stethoscope.
I turn on the ignition, ABS pump starts and the clicking stops. The pump runs for maybe 35 to 40 secs before it builds pressure and cuts out. So I suspect the accumulator needs changing. It has lasted 20 years.
Car drives and brakes OK. If I lock it again it is quiet for a few hours but the clicking returns. Presumably as the brake pressure drops.
Question ... what can the clicking be with everthing turned off?