Why Your Car Remote Works Sometimes But Not Always

A remote that fails completely is easy to diagnose. One that works most of the time, then does not, is the fault people put up with for months. There are usually four reasons.

A battery on the way out

A weakening cell has enough power in the warm, at close range, on a good day, and not enough in the cold at the far side of a car park.

If the failures correlate with distance or temperature, change the battery before anything else. Waikato mornings in winter are when these first show up — the same fob that was fine in March starts failing in June. The right cell and how to fit it is in which battery does your key fob take, or we will do the car key battery replacement at your door and test the range afterwards.

A worn button contact

The rubber pad under the buttons wears through where your thumb lands, so the contact only makes when pressed at a particular angle.

The giveaway is that pressing harder or differently makes it work. This is a repair rather than a replacement — see key fob repair — and it is one of the cheaper things we do.

Radio interference

More common than people think. Certain car parks, buildings and even nearby transmitters can drown out the signal.

If your remote fails reliably in one specific place and works everywhere else, that is what you are dealing with, and there is nothing wrong with the fob at all. Multi-storey car parks are the usual culprits. Walking a few metres away and trying again is the test.

A cracked case letting moisture in

This produces genuinely random behaviour, often worse in wet weather, and it gets steadily more frequent until it stops for good.

A crack that looks cosmetic is not, because the board underneath is what is being exposed. If the fob has been dropped and has since become unreliable, the two are related.

Deal with it while it is still intermittent

A fob that is repairable today becomes a full replacement once the board corrodes through. The economics only move one way.

Winter is when these surface

Waikato mornings from June onward are when a marginal fob finally stops working, because cold drops the voltage that little bit further.

If yours has been getting less reliable through autumn, deal with it before winter rather than during it — the same point is made in winter and your car locks.

Which side of that line yours is on is covered in repair or replace a key fob. Send the details through our quote form and we will tell you which it is likely to be.