Intermittent wiper interval

[graynada]

According to my handbook, dated 1994, I should be able to vary the interval on the intermittent wiper by switching to intermittent, let it complete a sweep, switch off and then switch back on again at the desired interval between 1.5 and 22 seconds. However what ever I do the interval stays at roughly 6 seconds.

Talking to Dezzy I asked him about this and when we checked his handbook, dated 1995 it doesn't mention being able to adjust the interval, and his car behaves the same way as mine, his car bing a '96 P reg, mine a 96 N reg.

I changed the wash wipe relay and this has had no affect.

Does any one know if I should be able to vary the interval, or was this a feature on '94 cars that was removed later, and (long shot) can it be retro fitted?