comprobar rele
comprobar rele

Comprobar rele:

You can easily test a relay in a few simple steps. The required materials are as follows

Digital Multimeter (with continuity setting)
12V power supply
(Optional) Aligator clips for hands-free testing
DO NOT USE YOUR BATTERY DIRECTLY FOR THE 12V SUPPLY, if you have nothing on hand and want to be safe please use a fused line from a harness or through the fuse box and not the battery terminals directly, to 12V wallwart (dc adapter for powering your typical consumer devices) with the connector cut and leads stripped is a good option as well. Crowbarring at 12V battery is a catastrophe which is scarilly easy to do with a relay with redundant pins and poor pin markings.

The test procedure is as follows

Determine relay number and pin out

Connect 12 V supply to Control pins on the relay and listen for a physical click (Gross Test). A relay that passes this test will probably be ok, but if you still suspect the relay you can easily verify finer electrical properties by continuing.

Disconnect Relay

Verify that all the Normally Closed connections read continuity and low resistance (a few ohms), verify that all the Normally Open connections read no-continuity and infinite resistance. The control pins should read a few ohms, but refer to the datasheet for the relay. A Relay may click from raw 12V, but a relay may not actuate under say ECU drive signal

Reconnect relay

Verify continuity across relevant signal pins (should read at most a few ohms and the DMM buzzer should go off). NO opens should be closed and NC pins should be open, for more complicated relays refer to the datasheet

This will verify the actuation of the relay, that a connection is established and is not degraded, and that the relay succesfully disconnects (not sticking) when unpowered.

A relay diagram looks as follows: enter image description here

The bouncy line indicates the inductive control element, and the straight lines with the break indicate the signal connections. A relay may have several redundant or parallel switching lines and possibly redundant control lines. This particular relay switches between 87A and 87 when the proper voltage is applied between pins 85 and 86. In this case, for step 4, Pin 30-87A is normally closed (NC) and pin 30-> 87 is normally open (NO)