Very easy to change. Most of them get full of water over time. The drain
hole at the bottom of the motor has a tube that gets kinked by stuff moving
around in the boot and hitting it.
Stick your head in the boot below the aerial and get someone to switch the
car radio on/off/on - you should hear the relay click. If you hear the click
followed by a brief rattle, then aerial is likely jammed. A click followed
by nothing is probably the inline fuse, on the wire next to the aerial, or a
knackered motor. No click indicates a probable wiring problem, or a faulty
A jammed aerial can often be freed by just gently pushing it into the
retracted position. Make sure you push straight down, any sideways movement
will buckle the tubular aerial elements.
Alec Wood M1BNK
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