Do these have the large double width window relay?
If so pop the cover off of it and check all solder joints for cracks.
On our 80A tye windows were permanently live then became intermittent. Then i found that someone had used a strip of cardboard to hold the relay 'on' to get round this solder problem

The red one is the problem here with a dull circular line aroud the joint, easy to miss when you first get the cover off.
Hth