<snip>
I Have a 88 westy that the fridge will stay lit when the fridge is out of
the van on the bench but will not when it is in the van.
<snip>

What's different when it's on the bench?  Are you using a different
regulator?  Have you checked the onboard regulator to see if it's up to
snuff or if maybe it needs adjustment?  What's different about the exhaust
and intake when it's out of the van?

Just questions ... but they are the ones I'd ask myself first.

Mike