T_Vert

This just started after putting in LED bulbs. When I open the door, the LED's under the mirror will not go on unless I open my sun visor and the light inside there goes on. Mind you when I flip the switch for the lights under the mirror to come on, those work fine. Anyone else run into this issue?

Thanks
Dave

lucky131969

While the rear view mirror lights share a common ground, they receive voltage from two different sources depending on operation. Pin A as a courtesy light, and pin B as a switched light. I would check the voltage value at pin A when the other courtesy lamps are on.

The intrinsic difference between the two modes of operation, and the mod that you did, is: you cannot control the courtesy lights individually. So when the courtesy lights are on, you have five lights in parallel.

The same is true with the switched operation(loads in parallel), but it is seldom that you would have both vanity lights, the underhood light, instrument panel light, and both map lights on simultaneously.

T_Vert

So there are two hots feeding the mirror lamp?

lucky131969

Correct.

T_Vert

Could this be because of the low load of the LED lamps for the rear view mirror? I noticed that if i open the visor once then the courtesy lights will operate as designed. I will have to see at what point they cease to operate as designed, maybe it is after the ignition has been turned off.

Dave