Just received the led festoon bulbs for my 85 Mazda Rx-7 dome light. When powered on they're very bright but there's an issue. When turning the power off the leds are faintly glowing, is it supposed to do this? I switched with other led bulbs and they do the same thing. Fearing the car battery would drain, I wound up reinstalling the oem incandescent bulb. Your thoughts on this appreciated!

 

I think it’s a switch problem I have regular bulbs and I have to turn my inside lights off, I have come out in the morning and they were on.

 

This brings up a good point. I might wire mine to only use switched power.

 

No issue on my 80. Do the 85s have a extra logic to sense bulbs out or missing for these? It could be a small voltage is being run to detect a missing bulb but I didn't think 1st gens had that.

 

Not aware if it does. Measuring the bulb connector, I'm not seeing voltage. However the map light has an led and doesn't exhibit any residual light after being turned off. Could it be a quirk of the leds in a festoon bulb retain voltage after being powered on?

 

It seems the switch is ok for the dome light but the leds still glow faintly when switched off, perhaps they need an adapter of some sort. I gave up and reinstalled the incandescent bulbs but found the 15a hazard fuse was now blowing. Earlier I had an issue with the dome light intermittently working and found the cause being one of the festoon bulb clips had a loose positive wire behind it. I secured it to the clip using a small screw after drilling out the tiny rivet that secured it then reinstalled the entire assembly to the ceiling, that's when the 15a hazard fuse started blowing. Removing the mirror dome light assembly again, I found a positive wire I connected to the festoon clip with a screw was raised slightly by the screw head and had been making contact with ground causing the fuse to blow. The connection was insulated by applying a dab of hot glue on the head then covered it with electrical tape. Reinstalled it and now the dome and map lights function as they should and seem brighter than before. Tip: If experiencing intermittent or poor light from the overhead, check the connections behind for corrosion or looseness.

 

Forgot to add , the area behind the assembly has limited clearance for the electrical and it's very easy to pinch the wires shorting them out to ground so make sure the wiring is recessed properly in the ceiling openings. I also found suspending the assembly by a stiff 's' shaped wire attached to the bolt holes in the ceiling and holes of the assembly while removing or installing puts less strain on the wiring.

 

Nice fix!

 

I think it’s a switch problem