How can I test the glow plug relay?

How can I test the glow plug relay?

Check them. The somewhat larger wire that is attached (via a brass bolt) to the preglow relay is showing voltage to the relay and is a good clean conection. There is no voltage from the 5 pins on the relay after turning the key to the point where the glow plug light should light.

How does the glow plug relay work in a Mercedes?

The Readout image by Cinneman from Fotolia.com Glow plugs heat the cylinders in diesel engines to help start them. The glow plug relay uses a small amount of electrical current to close contacts to supply higher current to the plugs. If you suspect the relay is bad in your Mercedes, unless you are a mechanic, you may have difficulty finding it.

Can you test a glow plug in a Mercedes?

If you can find the relay and remove it, it’s a standard Bosch automotive relay that you can test with two test leads and a multimeter. Glow plugs heat the cylinders in diesel engines to help start them. If you suspect the relay is bad in your Mercedes, unless you are a mechanic, you may have difficulty finding it.

How to choose the right glow plug control module?

If your glow plugs are all working correctly, move onto your glow plug control module. Start by checking the battery voltage to the glow plug control module, a voltage drop of over a half volt (or more) means your control module should be replaced. How to choose the right glow plug control module?

How do I test glow plugs?

Testing Glow Plugs in the Engine Grab a multimeter. Set your multimeter to ohms. Find resistance value of your multimeter. Test the voltage of the battery. Locate the glow plugs. Remove the caps or connectors to the glow plugs. Clip the multimeter ’s negative lead to a ground point in the engine.

How long should glow plug relay stay on?

The glow plug relay should stay on for up to two minutes depending on temperature. The wait to start light is not an accurate gauge of weather or not the GPR is on. You can test the relay with a multimeter to see if its working, but you may just need to leave the key in the run position for a few extra seconds after the WTS light goes out.

How to tell if glow plugs are working?

Part 1 of 1: Testing your glow plugs Determine the multimeter’s resistance value. Before testing the terminals, you must determine the resistance value of your digital multimeter. Locate the glow plugs in your engine. Most glow plugs are installed in the cylinder heads and will have a heavy gauge wire, similar to a regular spark Disconnect the glow plug wires.

Does computer control glow plug relay?

One thing to keep in mind is that the Excursions have a computer that controls the glow plugs, not a relay. The PCM (computer) runs the glow plugs (through the relay) for up to 120 seconds dependent upon engine oil temperature.