I've read some people saying that using the test light on a module is a bad idea. Is this a theoretical bad idea or have people actually had issues doing it?
O2 sensor heaters, Injectors, coils, stepper motors and relay coil all carry a current which is higher or similar to the current through an ordinary tungsten test light so they won't damage the drivers in the ECU. What you have to be careful about shorting a computer switched output to ground or directly to heavy load such as a fuel pump or fan motor.
The 5v ref on fuel level sensors , 2 and 1 wire temperature sensors generally pass through a resistance before they leave the computer so will survive a test light or even a short to ground.
The 5v reference to 3 wire sensors such as TPS, MAP and other Pressure sensors is pretty well protected and can survive being pulled down to ground
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Andy.MacFadyen wrote: O2 sensor heaters, Injectors, coils, stepper motors and relay coil all carry a current which is higher or similar to the current through an ordinary tungsten test light so they won't damage the drivers in the ECU. What you have to be careful about shorting a computer switched output to ground or directly to heavy load such as a fuel pump or fan motor.
The 5v ref on fuel level sensors , 2 and 1 wire temperature sensors generally pass through a resistance before they leave the computer so will survive a test light or even a short to ground.
The 5v reference to 3 wire sensors such as TPS, MAP and other Pressure sensors is pretty well protected and can survive being pulled down to ground
Got it. Thank you. I JUST got to section three in Paul's book that covers this as well.
