How do you check if a relay is bad? Is there anyway to check without just replacing?

 

If it is a full ISO relay, apply power and ground to the coil ( pins 85 & 86 ).

Measure the resistance over the Normally closed contacts ( 30 & 87 ), this should be 0 or close to it.

When you remove the power from the coil, the resistance should go to infinity.

Sample drawing :


If it is a Ford half ISO, the numbers change for the assignments, but the function is the same

 

wow SSCULLY, your awesome at these relays...... you helped me a bit the other day too!

 

Don't thank me until you find one that costs less then that Square D JCK type. Those are USD$ 100.00 + each !!

Elk might have them in the 30.00 range, and you would need to buy a small plastic enclosure for it ( usually bare, made for putting into a security cabinet ).