Join Date: Dec 2002
Location: Saint Louis, Missouri
Re: Any way to "Test" idiot lights?
To test a circuit like a TEMP idiot light, an OIL idiot light, or a high beam indicator, you just have to mimic what the sender needs to do to illuminate the light or what type of signal or voltage needs to be sent to things. The idiot lights also work with different positions of the ignition switch as well as the position of the headlight switch.
For instance, a regular TEMP idiot light gets a grounded signal from the sensor/sender to illuminate it but since you do not want to have it working all the time, and only when the engine is running, the other side of the light would get a source of power off of an ignition powered fuse. Some wiring designs had a self/test feature in that when the ignition switch was turned to the crank position, the temp idiot lights ground side became grounded to illuminate it and then once the key was released to the run position, the temp light was connected to the sender/sensor on the motor and if the sender was ungrounded the light would be off but if the engine was too hot the sender would be grounded internally and then the light would be on.
Most of the time the OIL idiot light did not have this self/test feature and like the temp idiot light, it too was powered by a fused ignition 12V source and then if the sender/sensor became grounded, the light would come on.
On a high beam indicator light, this normally was wired off of the high beam output of the floor dimmer switch and to tes tit,12V would get applied to the light and the other side of the light was grounded.
1974 Spirit Of America Nova (being restored), 1973 Nova Custom, 1968 Chevy II (Garage Find 2012)
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.