Lighting (or failing to light) the Fridge - help

[torchy]

I have the standard Dometic RM 182B gas fridge as favoured by Westfalia in countless installations...and now it won't light!

It used to but not now.a few facts.

I've cleaned out the air inlet and exhaust - no blockages.
Checked the air pump - OK
Plenty of gas you can hear it and smell it.
On the bench......When I remove the six screws holding the combustion chamber let it hang down and try lighting..It works no problem everytime!!
Screw it all back together again ...it goes "Poof" when I try and light, so clearly something happened but does not stay lit then I cannot light no matter how many times I "pump and press" according to the instructions.

My thoughts are it is not getting enough air to light or the piezo igniter is begining to fail.

I really hope to get this working again since I've just cut a 3 inch hole in the side of the van specifically for this unit!

With so many of these units out there hopefully someone can shed some light on this.

....and if it's the piezo unit,,,,where can I get a new one.???

Look forward to your comments and many thanks in advance.

Regrads

Peter

[lhd]

Can you hear the spark generator clicking? if so it should be working.
It could just be the the end of the spark lead, they can corrode and when they do they move out of the optimum position to light the flame.
Rob......