Explain these two relay types

[geeman237]

I’m not very good with the electrical side of cars. So can someone explain the difference in these two relay circuits please. Seems to me they do the same thing but in a different way?
In my case it is in context of a 1984 Lotus Esprit 3 speed blower motor circuit.

[Hawkshaw]

The difference is that in the second diagram, 87 and 87b are disconnected from each other as well as from 30 (usually the supply) when the coil is not energised. This might be important in some applications - would need to see the complete diagram to say whether it matters in your blower motor circuit.

[GreenV8S]

The second relay type prevents either of the output circuits from backfeeding the other when the relay is not powering them. Whether that's relevant to you would depend on what the outputs were driving and whether they were also driven from somewhere else.

[ARHarh]

In practise it will make very little difference as when the contact is closed they will be joined together. both will switch your blower on.

[geeman237]

Thanks for the replies. I think I need the second relay type. Here's the schematic for reference. Ignore my additions, I got the wrong type of relay at first.

[Polly Grigora]

Several websites have made a mistake when numbering the relay terminals as above, the 2 relays you've posted images of should be showing 2 x 87 terminals rather than a 87 and 87b

Below is a relay that has double normally open contacts which is correctly numbered with 87 and 87b, this type of relay is ideal for splitting the load of 2 motors across individual contacts