Probably a stupid question, but how do you check a relay -- and where do you get replacements if you need them? Can you get them from AutoZone like fuses? (My trailer running lights aren't working...most likely the relay)

Thanks!

 

I usually test one by swapping it with one from a working circuit. The trailer park lights should also have a seperate fuse under the hood. On a 2000 it's location #5 but check your manual.

 

Don't get ANYTHING in the zone. I collect OE relays in junkyards, but you can get them at any parts store, or even WM for some styles of relay.

 

If you want to test the item, you can try this ( pick the correct one, half or full ISO relay ).




The cost of Ford to Autozone relay is about a 5.00 or 7.00 delta ( 12.00 from autozone and I want to say 17 or 19 from the dealer on the street ).
Several here have used the Autozone replacement relay, without issue ( ~ 4 years ) and I had a Ford relay ( fuel pump ) go out in 4 years. Where it is purchased, is not as important as one would think ( autozone sells a big line relay company's product anyway, it is not an Autozone product ).
Friend's Honda Valk just had a Honda fog lamp relay take a powder, the coil was not pulling in, and just started clicking. Honda with their great build rep also has problems with their supplier at times.

You can either jumper the relay socket as shown above to see if the Normally Open contacts are passing power, or use a 12 V battery and a ohm / continuity meter to check to see if the coil when energized is closing the contacts. Power and ground to the coil ( 85 & 86 ) and meter on Common and normally open contacts ( 30 & 87 ). Once power is applied to the coil, 0 ohms should be the reading on the contacts.