Are relays reversible?

A relay is nothing more than a remotely located switch that you activate using a small switch or computer. The relay then has an IN and OUT (usually reversible) high current pins that break the high current line between the battery and the large lights.

What should I do if my power relay is not working?

Connect a test light between the battery negative terminal and the TCR B+ terminal in the fuse box. The light should illuminate. If it does not, there is a problem on the power side of the circuit. Consult the factory wiring diagram and repair the power side of the circuit as necessary.

How do you test a four terminal relay?

Confirm the current carrying ability of the load connectors. With the relay in the configuration that has the 2 load pins connected, place the test voltage on 1 of the load pins of the relay and an automotive test light on the other load pin of the relay.

Where is terminal 86 on a fuel pump relay?

The (PCM) grounds the coil side of the relay through terminal number 85. Terminal number 86 supplies voltage to the coil side of the relay. When the (PCM) de-energizes the (ASD) and fuel pump relays, terminal number 87A connects to terminal 30. This is the OFF position.

How to check the power of the Transmission Control Relay?

Remove the transmission control relay. Turn the vehicle ignition on and use a test light to check for power to the TCR. Connect the test light between the battery negative terminal and the relay control terminal in the fuse box. The light should illuminate.

Are there two relays in the outside fuse box?

than there is two relay in the outside fuse box the control high and low fans. and two relay for this system. If you have 12 volt here than check the relay for power at pins 25 on the low relay should be hot with the key on and pin 4 on the high relay should be hot with the key on. You will need a volt ohm meter for the tests.

What to do if your AC compressor relay is not grounding?

But before splashing $100 on a replacement PCM you better be DARM sure the relay control ground wire is making contact with the above mentioned pin on the PCM. You can always use a meter to check if the PCM is working. Just connect one probe of the meter to the battery positive voltage and the other to pin 27 of the PCM.

How do you check for a faulty relay?

The only tool required to check a relay is a multimeter. With the relay removed from the fuse box, the multimeter set to measure DC voltage and the switch in the cab activated, first check to see if there are 12 volts at the 85 position in the fuse box where the relay plugs in (or wherever the relay is located).

How can you tell if a relay has a blown fuse?

If voltage is able to flow through that side of the relay, move on to the 87 connection point and determine if battery voltage is present there. If it isn’t, that also suggests a blown fuse or circuit breaker. Checking the connection points in the fuse box with a multimeter will confirm if battery voltage is available at the relay terminals.