Thread: Hazard lights on constantly

Greetings, My 2001 TD5 has an issue with its hazards lights staying on. Occurred while driving after approx. 3 hours non stop and only remedy at the time was to pull indicator fuse. I spent several hours searching threads regarding inertia switches and the like and have eliminated this as a cause (car still starts and runs and I've tried bridging switch). Things I have noticed.....if I disconnect battery and reconnect the hazards will not come on until I turn the ignition on....If I refit fuse they come after approx. 10 secs. regardless of ignition position. Is this some sort of indication of a more serious problem ie faulty airbags or ABS??? Live a long way from a dealer to get diagnostics done and don't really want to pay for a nanocom if its an easy fix...Please any help would be appreciated

I'd say that the problem is rather with the IDM(part of the interior fusebox) than BCU, the only simple way to rule this out is to swap the fusebox with a known good one cos that's plug and play(only thing you must do is to disconnect the battery first, swap the fuseboxes and after you reconnect the battery put ignition on pos II and leave it so 5 minutes as the IDM to establish full communication with the BCU otherwise it can be immobilised... then start the engine and if the problem persists then you know that the BCU is suspect but for this one you need a tester to programm it

not easy at all... try to unplug the hazard switch to rule it out even though if it was blocked closed the hazards should stay on even without engine running but worth a try

there is a chance to find out if it's teh BCU or IDM but for that you must cut a wire then solder it back, it's the wire which connects the BCU to the IDM on the hazard lights circuit so if the symptom persists with it interrupted it's the IDM if not it's the BCU...if you are up to do that and you have RAVE just let me know