LEDs let the smoke out of my headlight switch?

[Nditiz1]

So I'm in the process of switching out my fresh air controls from a single top lever to a dual one because it allows you to control the AC better (ClassicRetro installed). Anyway I thought it would be nice to upgrade 50 year old tech with some nice warm led bulbs much like are installed in my gauge cluster. The fresh air has 4 tiny (2721?) bulbs installed for when the lights are on OR when you turn the fan on. Well I wanted to test out everything before fully securing the controls again. With 3 of the lights dangling out the bottom I tried to turn the lights on with the ignition off. No lights, ok well maybe I need the key on. Turn to on position, pull knob, no lights, no lights in gauge cluster, hmmm start looking around, see smoke, great... Looks to be a fired switch and nothing more. Are the LED bulbs I put in somehow breaking the laws of energy disallowing better tech to be installed in this 50 year old rig? I briefly tried to run the fresh air motor just to see if that all works and it did, but not before blowing fuse 8 on the front fuse box. This would have activated the led bulb behind the fan icon in the fresh air controls.

I will be adding the inline fuse so as to not let out anymore smoke from future switches as well as the Jwest relay.

Also, I need to find out where this wire belongs as it was not on its connection point when removing the headlight switch

[rothaus]

Can you post a picture of the LED you installed ?

[Nditiz1]

Engelbert - here are the pics. I am just noticing a +/- icons. I did not think there was a difference in polarity for these types of led bulbs. BTW I did check your website and saw this type, but wasn't sure if they were in green or white, that and saw you were out of town for a few weeks.

[rothaus]

Those LEDs have the plus on one small side and minus on the other small side. So they have plus on both sides, as well the minus. The normal bulbs have the + and - at the flat side, see picture below. If you look at the original bulbs, you can see that the little wire is once on one side and the other on the opposite flat side. So basically making a short with those leds.



Does this make sense ?

If you saw the green T5, they are to large and will not fit in the socket for the air control light.

Cheers
Engelbert

[1979-930]

That is probably the power wire to the automatic radio antenna.

[Nditiz1]

Thanks Engelbert. That makes sense. So if a strip a contact from each side then it work as intended.

Thanks Derrick. I will tape it off better so as to not create a short in the future.

[timmy2]

Black/Red is supposed to run from 58a of the light switch to a resistor N6 coming from terminal 58 of the emergency flasher switch. It is to limit the current to the light on the flasher switch.
Likely there is a open terminal to the resistor coming from the emergency flasher switch back there.

[GH85Carrera]

The factory decided that fuses for several circuits were not really necessary. They were very wrong!

You need to add a fuse for the instrument lighting, the front condenser blower next to the battery, and the footwell blowers. All of them can and have caused fires, and the loss of the car.

When checking the function of the instrument lights, they really need to be in place in the instrument. The grounds are provided by the instrument itself. With those bulbs just dangling, it is super easy for one of them to be touching a ground with the power side and you get smoke and panic.

[Nditiz1]

Dennis/Glen - Thanks for chiming in.

The housing of the fresh air control lights are not grounded via the device. They plug into the plastic housing of the face. Another reason I wanted to switch to LEDs is that I have noticed the housing where they fit are sometimes warped from the heat of the bulb.

You are very correct about making sure they are in place for the gauge cluster and possibly even the switch itself.

[timmy2]

Put an in line fuse (3 amp ATO type) between the terminal 58a on the switch and the 2 wires currently installed on that terminal.
For your 77, the fresh air blower motor is fused at Fuse 15 (counting back from headlight) Blue wire.
No footwell blowers. No front condenser with your electric A/C.

[timmy2]

Lol, someone asked about the other end, look for this guy.
https://forums.pelicanparts.com/porsche-911-technical-forum/1113232-another-wire-question.html

[Nditiz1]

I did see the brown wire coming out of the hazard with a male spade and nothing connected to it.

[timmy2]

Trace it to the lamp socket in the hazard switch and confirm.