Dome light fuse blowing

[69 R/T]

My 69 Coronet for some reason blew the dome/console light fuse. As soon as I insert a replacement it blows out, so obviously there's a short somewhere. I pulled the fuse block out and it's got about 5 piggyback wires on that circuit. One of them was added on to feed the tach, but the rest look like they're Factory. Any thoughts on what could be causing this? I wasn't working on the car or anything, however it occurred right after I power washed the engine.

 

[Lionized]

Remove the tach power wire and then replace the fuse.
Does it still blow?

 

[bm02tj]

Check for a pinched wire under rear seat
That is what mine was
it only blew when some one used back seat

 

[69 R/T]

Remove the tach power wire and then replace the fuse.
Does it still blow?

Yes, that was my first thought. I ran out of fuses, so I gave up and went on here to ask.

 

[69 R/T]

Check for a pinched wire under rear seat
That is what mine was
it only blew when some one used back seat[/QUOTE
I wasn't in the back seat doing any cleaning. I power washed the engine compartment and washed the car. The windshield seal leaks a bit in the drivers side corner. Could a water leak cause this?

 

[Billccm]

Recalling from memory; Chrysler built some safety into the dome light. If your dome light is out you don't have brake lights.
Had the same problem on my coronet back in the day. It was a tail lamp socket shorted to ground. The contact spring in the socket broke and shorted out the entire socket.
This is probably not your problem as the fuse is blowing without actuation of the brakes.
Get a test lamp and place across the blown fuse location. It should glow bright indication of the short. Start unplugging the wire branches until the lamp is off. There's the short.

 

[69 R/T]

Great idea....I'll try that. Thanks!

 

[69 R/T]

I made a mistake I was in error I checked the fuse block they are on the same circuit as one's on the hot side and one's on the fuse side.

 

[69 R/T]

Could a slight water leak a the lower left windshield cause a short? Sometimes when I wash my car a little bit of water leaks past the seal and goes down underneath the dash.

 

[Shorthorse]

Could be the power washing but most all those connections are in the interior except for the brake lights and the trunk light and they go toward the rear.
That fuse is un-switched and has power at all times from the battery. The input for that fuse is a red/tracer wire tied to the main power lead in the harness. There are 5 wires on the output of that fuse, 1 gray and 4 pink.
Gray - clock
Pink 1 - Glove box light switch
Pink 2 - Emergency flasher and stop light switch
Pink 3 - Dome light, console lights and trunk light switch (courtesy lights).
Pink 4 - Map light
The important thing to remember is that the courtesy lights have power at all times and work via a switched ground from their respective switches. Things like the stop lights are actuated by switching battery.

http://www.mymopar.com/downloads/1969/69CoronetA.JPG
http://www.mymopar.com/downloads/1969/69CoronetB.JPG

 

[69 R/T]

Could be the power washing but most all those connections are in the interior except for the brake lights and the trunk light and they go toward the rear.
That fuse is un-switched and has power at all times from the battery. The input for that fuse is a red/tracer wire tied to the main power lead in the harness. There are 5 wires on the output of that fuse, 1 gray and 4 pink.
Gray - clock
Pink 1 - Glove box light switch
Pink 2 - Emergency flasher and stop light switch
Pink 3 - Dome light, console lights and trunk light switch (courtesy lights).
Pink 4 - Map light
The important thing to remember is that the courtesy lights have power at all times and work via a switched ground from their respective switches. Things like the stop lights are actuated by switching battery.

http://www.mymopar.com/downloads/1969/69CoronetA.JPG
http://www.mymopar.com/downloads/1969/69CoronetB.JPG

Thanks for that info, Shorthorse. My plan is to remove all the wires from the piggyback for that fuse position with the doors closed, insert a new fuse (it shouldn't blow with no wires connected), open the door then attach one wire at a time to determine which wire has the short. The fuse blows when I insert it with the door open, so I'm assuming it's in the lighting circuit and not the stop lights. That's my day off event prior to Saturday's car show.

 

[threewood]

If my memory serves me correctly, the dome, courtesy, console lights and trunk are all on the same circuit and turn on when the door switch is grounded (or truck switch, if you have a trunk light).

The main connectors are behind the driver side kick panel. (I want to say the yellow or pink wires) check the connections behind there. The console wiring runs right under the driver seat and the trunk light wire runs straight back under the wire protector along the sill, around the wheel housing and up to the trunk light. Check the wire for any breaks or rub throughs.

 

[threewood]

 

[oldbee]

If my memory serves me correctly, the dome, courtesy, console lights and trunk are all on the same circuit and turn on when the door switch is grounded (or truck switch, if you have a trunk light).

The main connectors are behind the driver side kick panel. (I want to say the yellow or pink wires) check the connections behind there. The console wiring runs right under the driver seat and the trunk light wire runs straight back under the wire protector along the sill, around the wheel housing and up to the trunk light. Check the wire for any breaks or rub throughs.

Dome,courtesy,etc. are hot all the time(door open or closed) you may have some water going from w/shield down to wiring below emer.brake?

 

[69 R/T]

If my memory serves me correctly, the dome, courtesy, console lights and trunk are all on the same circuit and turn on when the door switch is grounded (or truck switch, if you have a trunk light).

The main connectors are behind the driver side kick panel. (I want to say the yellow or pink wires) check the connections behind there. The console wiring runs right under the driver seat and the trunk light wire runs straight back under the wire protector along the sill, around the wheel housing and up to the trunk light. Check the wire for any breaks or rub throughs.

Thanks, Threewood! Great reference photo. That minor windshield leak may have gotten water on that connection after I washed the car...that's when it happened.

 

[69 R/T]

Dome,courtesy,etc. are hot all the time(door open or closed) you may have some water going from w/shield down to wiring below emer.brake?

I completely agree!

 

[Wietse]

As per original drawing the fuse for the dome light is also supplying the cigar lighter, which i my case caused the same issue you are describing.
This fuse indeed has a direct un-switched supply from the battery positive and through the amp meter.
The fuse is linked with a bridge to supply other lights etc, but in the end they all are protected by another fuse.

IF everything is still original it can only be the cigar lighter.
You can try it and remove the red wire from the back of the cigar lighter and try again.

 

[69 R/T]

As per original drawing the fuse for the dome light is also supplying the cigar lighter, which i my case caused the same issue you are describing.
This fuse indeed has a direct un-switched supply from the battery positive and through the amp meter.
The fuse is linked with a bridge to supply other lights etc, but in the end they all are protected by another fuse.

IF everything is still original it can only be the cigar lighter.
You can try it and remove the red wire from the back of the cigar lighter and try again.

Thanks, Wietse. My cigar lighter socket is dead prior to the fuse blowing, by the way. My phone charger wouldn't power up, that's how I knew it wasn't the actual lighter. The car was restored in 2000 and it still has all the original wiring and the dash was never cut up for an aftermarket tape deck. The stop lights run through this circuit too, because I have no brake lights either.

 

[Billccm]

Like I said earlier, the safety feature of the dome light is to alert the driver of a possible loss of brake lamps.

Try the test light method of finding the short.

 

[69 R/T]

Like I said earlier, the safety feature of the dome light is to alert the driver of a possible loss of brake lamps.

Try the test light method of finding the short.

That's the first thing I will try, Bill. That way I can isolate and trace the problem wire. Thanks for your sage advice!