A264172,

Finally did the test correctly as follows, on both my current and the brand new OVP:

"Test 1: Connect pin 30 to a +ve 12v supply and pin 31 to the -ve. Under this condition the only output should be on pin 30a.

Test 2: In addition, now connect pin 15 to the +ve and both relays should operate with supply voltage now also appearing on both pin 87E and 87L (so all pins 'live')".

Both my OVPs passed with flying colours (note, there is an audible 'click' as power is added to pin 15).

My understanding is this is a fairly basic test: one up from checking the fuses are intact; that it doesn't rattle when you shake it; and that there's no cr@p around the pin connections.

If it fails this test you are pretty sure the OVP needs replacing, if it passes it though, there is still the possibility of an intermittent fault caused by something like a weak solder joint.....

Will post this test info on the thread link you gave in-case it's of use to someone else.