If you own a diesel car, particularly a Mercedes, you might encounter problems with the glow plug timer relay. This component is essential for the engine to start when the climate is very cold since it heats the glow plug for easy ignition. The glow plug timer relay is responsible for managing the time given to the glow plugs to heat up before the engine starts, so if this relay is faulty, it can cause starting issues and low engine efficiency. Below are tips that will help you diagnose some of the problems with the glow plug timer relay in your Mercedes.

Signs of a Defective Glow Plug Timer Relay

An obvious indicator that the timer relay is faulty is when the engine does not start easily, especially during the colder seasons. It may take several turns of the engine key to start or the vehicle may not start at all. The indicator light on your dashboard is something that you should also pay attention to. It must light up when the ignition key is turned otherwise, this could be a sign that the timer relay is faulty.

A faulty relay can also make the engine shake at idle and sometimes stall, or start up very roughly. This is because the glow plugs may not be as hot as they should be and so combustion efficiency is affected.

How to Troubleshoot Glow Plug Timer Relay Defects

Look for the Glow Plug Indicator Light

Begin by checking the glow plug light indicator on the car’s dashboard. If you insert the key into the ignition and turn it to the ‘on’ position, the glow plug light should come on. If it does not glow or is on for a longer time than it should be, then there is a problem with the relay.

Test the Relay

To diagnose the timer relay, you can use a multimeter. The relay is commonly located in the engine bay but you should check your Mercedes manual to be sure. Remove the relay from the socket and set your multimeter to the continuity or resistance. Place the two probes of the multimeter across the relay terminals. If the relay is in proper working condition, then the multimeter should display continuity. If there is no continuity, then the relay is probably bad and it is time to get a new one.

Inspect the Glow Plugs

Another component that can also be faulty is glow plugs, which can cause starting problems, so they must also be checked. Very gently take out the glow plugs from the engine. Switch your multimeter to the resistance scale and take the resistance of each glow plug. If a glow plug has high resistance or if it does not display any continuity, then the glow plug is bad and must be changed.

Check the Wiring

Check the wiring circuit of the timer relay and the glow plugs. Examine the wires for any sign of damage such as cuts, rust, or any loose connections. Defective wiring can cause problems for the relay and subsequently affect the starting process.

Listen for Relay Clicking

When you turn the key to start, the glow plug timer relay should make a faint clicking sound. If you do not hear this sound then the relay could be at fault.

Consult a Professional

If you cannot figure out what is wrong with your car, then it is advisable that you seek the assistance of a professional mechanic. The experts have the equipment and skills to identify and solve problems that relate to the glow plug relay and other related parts.

Kruse Lucas Imports: Your Trusted Partner in Mercedes Care

If you are in search of an experienced and reputable auto shop for taking care of your import vehicles, be it the German or Asian models, then you should consider coming to Kruse Lucas Imports. Our technicians are experienced mechanics who are able to work with any model of Mercedes.

If your diesel-powered Mercedes is developing glow plug relay problems, we are in a position to identify the problem and repair it. Our shop is based in Modesto CA, though we are also proud to serve drivers from Manteca, Oakdale, Ripon, and Turlock CA.