The Techko S087 alarms - are they for windows and doors? How many 9volt batteries does each unit hold?

BATTERY REPLACEMENT Always turn off power to smoke alarm before replacing battery.
Replace battery at least once a year, or immediately when the low
battery signal sounds (a beep once per minute indicates low bat-
tery). Batteries should be replaced regularly as necessary, even
when the smoke alarm is receiving AC power.
Use only the following batteries as replacements in this smoke alarm: Eveready 216, 522, 1222, Duracell MN 1604, or Ultralife U9VL-J [Alkaline batteries 9Volt] DO NOT USE RECHARGEABLE
BATTERIES.

1. Turn off power to smoke alarm at main service panel.
2. Turn smoke alarm counter-clockwise to detach from mounting plate.
3. Gently pull down smoke alarm. Be careful not to separate wire
connections.
4. Pull out power plug from back of smoke alarm.
5. From back of smoke alarm, lift tab to open battery pocket door.
6. Remove battery from pocket. Disconnect and discard bad battery from battery connector.
7. Connect a fresh, 9-volt battery to connector. The battery will fit
only one way. Be sure battery connector is securely attached to
battery terminals.
8. Place battery into battery pocket.
9. Close battery pocket door. Push down until it snaps into place.
10. Replace connector plug. Connector will "snap" into place.
Gently tug connector to be sure it is attached properly.
11. Reattach smoke alarm to mounting plate by turning smoke
alarm clockwise until it snaps into plate.
12. Turn on power and test smoke alarm using Push-to-Test button

if it's an old one, it's probably safest to simply replace it. alternatively, you could check to see if it has a backup cell (like a large watch battery) inside that might have gone dead and needs to be replaced. if the detector is rather new, you might want to take it back to the store and see if they'll replace the unit under warranty.

Check battery clips for corrosion, if okay! try a fresh battery first, if no change the unit must be dismantled to inspect the 9volt red and black wires inside to make sure it has not broken free.

He said it had a new battery so he already did that and why would you service a $12 throw away smoke alarm? This FIREX he identified is the 4618 and will also chirp while the LED light blinks, chirp is about 30 seconds after blink if the unit itself needs to be replaced because there is something wrong with it as opposed to a different chirp pattern for battieries. If still unerwarrantee FIREX will replace otherwise go buy a new one.

What is actually the problem, "Actually seems to work", what doesn't work.
If Toyota are on about the 9volt battery back up siren then the main siren may be working fine, but that might not be. Most cars especially Vauxhalls have a 9volt battery back up siren, so if someone tries stealing you motor and they disconnect the battery the 9volt battery will keep the siren going off.

if you have the siren added to the system, there is a special 9volt battery in side the siren unit and it has reached its usable life and needs replacing. if you do not have a siren replace the batteries in the key fobs low voltage on them can also cause a problem.

The normal condition for the green LED is solid. A flashing green LED indicates memory of a prior alarm condition. Press the test for at least 2 seconds to reset the detector memory.

One side has a magnet that holds a switch in the other side open until a door or window is opened and moves away from the magnet. Then the switch closes and the alarm sounds.

Check battery ffor correct polarity?

conect back the battery close all doors and windows driver door insert the key unlock the door one time and hold the key until window goes all way down then turn key to lock the door hold to lock position until windows go up if no stop repeat one more time right way without taking the key out , hope this help.