- Oct 10, 2014
- 312
- 294
- Funster No
- 33,775
- MH
- Hymer B680 Starline
- Exp
- We are no longer Newbie's.
Can anyone tell me how I can determine whether a door reed switch is a "normally open" or "normally closed" one? The van is fitted with a Cobra alarm and all the doors have reed switches, with the wired section fitted to the frames and the magnetic bit on the door. I have one which doesn't trigger the alarm when the alarm is switched on and the door is opened. I can access the wires on the back of the reed switch but I am not sure what I should be measuring with a multimeter to work out the type. Can anybody advise the best way to test as there are no markings on any of them which would give a clue. I am assuming it is the switch and not the wiring so knowing what I should be seeing whilst testing would be useful to work out what is wrong.