Either the battery has a bad cell (five charged cells and one dead one = ~10.5v battery) or it is simply not charging. Once the batt is solidly into >12v territory, your relay clicking should stop. A spare headlight bulb/pigtail with some alligator clips on the end works nicely for this. It helps to occasionally put a small load on the batt to remove the 'surface charge' and get an accurate read. With little benchtop trickle chargers, it can be a little harder- I'll usually periodically disconnect the charger and check the batt voltage to see if it's slowly building. With a 'full size' batt charger, you can then generally just look for charging voltage somewhere in the realm of what your typical alternator would put out. It cannot complete its task, but has just enough voltage to power up and keep trying, hence clicking relays.įirst check 'open circuit voltage,' which simply means see what you're reading at the batt terminals while disconnected. a BCM or other interior module is trying to manage basic functions like door locks, keyless/alarm stuff or whatnot. With the key off, there really shouldn't be, anyway, but sometimes in a modern car things get kind of stuck in a loop as the electrical system 'settles' after a shutdown. If the relay(s) keep clicking, the battery is probably not charging or there is otherwise a power delivery issue (bad cable to fusebox).įirst thing I would do is pull the battery from the car so that there is no draw on it. The relay coil gets just enough juice to pull the switch shut, but can't maintain it and the relay clicks back off. 'dead dead'.for all intents and purposes, no charge present. I've seen it on batteries showing only 6-8v or so.

Well below the 11-12v range of what is generally considered indicative of 'fully dead' or close to it. Repeated clicking from relays is common with a dead battery. Get a voltmeter and know with 99% certainty where you stand. Broken record/dead horse response from me:

Battery charger needle not moving