Should a neon be open circuit when there is no mains supply

[electricans_son]

My shower isolator, a MK 3164 whi 50A ceiling switch was not working, I found that that the two neutral terminals were not tight, the associated copper wires slightly burnt and there was a crack in the back of the switch. Consequently, I replaced it with another 3164. The switch works, ie the shower water heated up, but the neon does not light. Before replacing it with a second 3164, using a multimeter, I measured the resistance between the live load terminal and the neutral load terminal of the second 3164, with the switch in the on position, and it is open circuit, ie the needle did not move a jot from even ~1,000,000 ohms. Does that mean that that neon is faulty too?

I have had enough today, Saturday and intent to fit it tomorrow, so I thought I may save myself the trouble if the neon in the second 3164 is faulty, particularly as the packet had already been opened: I did not notice that when I bought it.

This shows the back of the 3164:-

3164 WHI | 1 Way Ceiling Switch, 1.5m, 50 A | MK

I put my multimeter probes across the two terminals nearest to the two black leads, these lead to the neon.

Note, the original faulty 3164 was fitted by a certified electrician!

EDIT:

I note that there are three small 5 mm long bulges in one of the neon leads, maybe indicating that there are some tiny devices in series with the neon.
.

 

[telectrix]

take the neon out of the old one and fit into the new one.

 

[Octopus]

I would return the MK crxp and buy a Crabtree 50A shower isolation switch for starters....

 

[electricans_son]

Thanks telectrix, but I thought of doing that, I tried to remove the neon from the original burnt 3164, but the terminals are a push fit and do not look like they are meant to come out because I can only get one wire out, the other is stuck in and it looks like I have damaged it.

 

[HandySparks]

A multimeter won't have a high enough test voltage to trigger a neon, so it'll show maximum on the resistance scale. If you tested it with 100V, then you'd get a reading of less than 1Mohm.

 

[electricans_son]

Thanks HandySparks, the second 3164 works fine and was easy to fit as I had previously cut the tails to a perfect fit in the isolator and the box.