keep blowing a fuse - light switch?

[Brian DePouli]

On my 1969 Charger. Whenever I engage the light switch on I blow a 20 amp fuse (second from the right) This is the fuse that also has the cigar lighter (not connect), console shift indicator light, and a few accessory lights I don't have. When the fuse blows I lose instrument panel lights, the clock, taillights and parking lights.

headlights (high and low), flashers, turn signals, brake lights, dome and console lights all work regardless of the fuse.

The fuse blows on either parking or full lights.

I've replaced the light switch and it still occurs.

parking lights are grounded as evidenced by them working as turn signals. Same for tail lights and headlights.

I've been studying the wiring diagram and I cannot come up with a reason/solution?

Anyone else have thoughts or experience with this? I am at a loss.

Thanks.

 

[kiwigtx]

The dimmer coil may have distorted out of the holder, and shorting on the frame of the light switch....although you said you replaced that.

Check the foot dip switch

 

[Brian DePouli]

The dimmer coil may have distorted out of the holder, and shorting on the frame of the light switch....although you said you replaced that.

Check the foot dip switch

Dimmer coil has been NOT been replaced yet. I have one spare that's not as nice chrome wise and I don't want to use from a show perspective but i can use it to check to see if it blows fuses. it was on the car per-restoration when this problem didn't exist.

foot switch seems to work as intended as headlights hi and lo come on and do not effect weather or not I blow a fuse.

Of note I am using LED bulbs in the instrument panel lights and a few other locations.

 

[kiwigtx]

Of note I am using LED bulbs in the instrument panel lights and a few other locations.

Make sure that these LED's are of the correct length on the base - there may be an issue with the contacts pushing into the holders too deep. Just a thought.

 

[Don Frelier]

Do you know if all the led bulbs are good? Or no short to ground?
I would check them individually, just because they are new parts doesn't mean they are good.

 

[Brian DePouli]

Swapped the dimmer switch. Just took the plug off the back and plugged in the new (old) switch and grounded it to the switch casing still in the car. Blew the fuse even quicker, immediate instead of 2 seconds.

 

[Billccm]

Put a test lamp across the fuse that keeps blowing. This will save fuses and your wiring as you troubleshoot, and give an indication of the short.
The test lamp glows bright during a short. Start unplugging the branches of the circuits and trace to the short.

 

[Brian DePouli]

Think I found it. the 1156 LED taillight bulbs were shorting. don't have any spares or incandescent so gonna go to wally world to grab some and confirm, but no fuse blowing with out them in at the moment.

 

[kiwigtx]

Think I found it. the 1156 LED taillight bulbs were shorting. don't have any spares or incandescent so gonna go to wally world to grab some and confirm, but no fuse blowing with out them in at the moment.

One of the LED's may have gone bad when installing them.

 

[Don Frelier]

Your welcome.