Relay Question

How can I tell if I have a bad relay? I'm looking at my 4WD relay and I pulled it out, but don't really know how to tell if it's bad.

My 4WD wont engage for some time now, and I've searched the forums, but am not technical enough to try the other suggestions, and will have to take it in, but thought i'd check this 1st.

Thanks.

1996 V6 4WD Rodeo.

Are there other relays of the same size/type in the relay/fuse box? If so, try swapping them over.

Yes there is, I'll try that.