Quote:
Originally Posted by flak_monkey  Never use a test light in a car with a BCM. NEVER EVER EVER EVER EVER. In fact, I wouldn't use a test light on any car with a computer. You don't want to test the wrong wire at any point in the vehicle and have an airbag deployed in your face. I've seen it happen with test lights, it's very dangerous and very painful. You can also damage sensitive electronics. It's standard practice to use a DMM for all electronic circuit testing in newer cars. Multimeters have continuity testing as well, you don't need to use a test light. |
That may be one of the dumbest things I've seen on this forum in a long time. I would have found it really funny if you weren't so deadly serious.
I never recommend using a test light on sensitive circuits such as solid state electronics or the air bags. But a test light is much more convenient in many cases where the presence of power rather than the amount is the concern. Most electrical problems involve simple circuits such as lights, signals, horns, etc. and a test light is the quickest and easiest way to test for power.
Of course you don't just start poking wires indiscriminately - you test wires that you already know should have power. I think you are thinking more of situations where you're trying to find a wire that does something in particular (e.g. searching for an ignition controlled power wire under the dash). Installers who don't have the schematic for every vehicle are well advised to not use a test light to locate the wires they need. But that's a completely different situation from saying "test the light blue wire in the socket for flashing power when the turn signal is on". In this case, there is absolutely no danger of damaging anything by using a test light to test for constant power on the two orange wires at the amp connector.
It's a case of using the right tool for the job. Sometimes a test light is the right tool, sometimes it's not.