I'm trying to ascertain whether I have a duff abs warning relay. Its a small blue relay with part No: 61311459675. 

I have the relay out on the table and I ran my meter over the pins and there was a reading between terminals 30 and 87 (2.0 ohms). My brother says there shouldn't be a reading there and thinks the switch has welded together. I opened it up and can confirm it isn't welded and can be easily prised apart with a small screwdriver. When the contacts are apart - there is no reading/bleep.

Q. Should there be a reading between these two pins?

The 30 and 87A relay contacts are supposed to be closed when the coil power is off.  That you are reading continuity when holding it in your hand means they are closed like they should be. 

87 is a normally open contact.  It closes when the coil is powered.

87A is a normally closed contact.  It opens when the coil is powered.

Hope this helps and be sure to show it to your brother.

If there is no 87A on the relay, it is the wrong relay.

Thanks very much .75.

Youre right. It is 87A (my eyes are past their best)

I'll have great pleasure in telling my big bro he's wrong 

Are you sure that it isn't 0.2 ohms? I just tested four of them that I have and they all measured about 0.2.

Even 2 ohms is a very small resistance though and essentially a closed circuit.

I mentioned my eyes were getting worse, so I just double checked on the 2 relays I have.

Both read 2.0 ohms 

Duck, the cheap meters I use don't go much lower than 2-3 ohms even when the probes are touched together to check the "zero".  I usually figure anything below 4-5 ohms is continuity.