Defender Won't Start? ECU Relay Could Be Your Culprit

Hi there! I have some experience working on cars, and I dealt with a similar issue on my 2004 Discovery diesel a couple of years ago. It was super frustrating when it wouldn't start! After getting stuck a few times, I took it to my regular workshop. They diagnosed a faulty main relay, exactly what you're suspecting. The fix was pretty straightforward, and it cost me around 120 Euro including parts and labor. Since then, no more starting issues! Quick question though, what symptoms are you experiencing exactly? Is it completely dead when you turn the key, or are you getting any dash lights? Also, have you checked the battery? Knowing these details would help me share more specific insights from my experience. Take care!

Hey, thanks for sharing your experience! My Defender has been really reliable up until now (161524 KM on the clock, last serviced just 2 months ago). When I turn the key, I get dash lights but absolutely nothing happens when trying to start, no clicking, no cranking, just dead silence. Already checked the battery and it's showing good voltage. Interesting that you had a similar issue with your Disco. Relieved to hear it was a straightforward fix! I'm kind of hoping it's just the relay too, as that sounds way better than dealing with a major electrical problem. Did your mechanic mention any specific testing they did to confirm it was the relay before replacing it? Thanks again for the help!

Hey! Yes, actually my mechanic did quite a bit of testing before confirming it was the relay. They used a multimeter to check the voltage at different points and performed what they called a "relay bypass test." The symptoms you're describing are exactly what I experienced with my Disco, dash lights but total silence when turning the key. One thing my mechanic mentioned was that these relays often fail due to constant use and heat cycles. Mine had about 155,000 KM when it failed, so yours failing at 161K sounds about right. They showed me the old relay afterward, and you could actually see some slight discoloration on the contacts. Quick tip from my experience, when they replaced my relay, they recommended getting a genuine Land Rover part rather than an aftermarket one. I know it costs a bit more, but it's been totally worth it. They said they'd seen some aftermarket ones fail within months. Do you mind keeping me updated on what you find? I'm curious to know if it turns out to be the same issue. These older Land Rovers can be quirky, but they're great vehicles when everything's working right!

Thanks so much for all that detailed information! It's really helpful to know about the testing process and especially that tip about sticking to genuine parts. The similarities between our situations are quite striking, same symptoms and similar mileage too. I've just booked my Defender in at the workshop for tomorrow morning. I'll make sure to ask them about doing the relay bypass test you mentioned and will definitely go for the genuine Land Rover relay if that turns out to be the culprit. The extra cost seems worth it to avoid dealing with this issue again in a few months! Your experience with another vehicle in the Land Rover family has been super valuable. It's great to connect with someone who's been through the same thing. I'll try to remember to update you once I get it sorted. Thanks again for taking the time to share all this, really appreciate it!