‘77 280z signal fuse keeps blowing up

[240zadmire]

Greetings

 

I’m scratching my head last couple of weeks and couldn’t figure it out.   I have the wire schematic and trace all the wires pertaining the signal fuse keeps blowing up.  I’ve clean the multi switch at the steering wheel, 3 times.  Unplugged/plugged back connectors at the passenger side and near the fuse box couple of time already.  The fuse seem to last for couple of days the blow up again.

 

the hazard switch and light work.  I just couldn’t figure where the short wire is that cause the signal fuse blowing off

 

any suggesting where else to look?  Thanks

 

[Zed Head]

The plastic bulb sockets have been known to get hot and deform allowing the electrodes to move and touch things they shouldn't touch.  You might pull all of your bulbs and check the sockets.

The fact that the fuse lasts a few days suggests that it's not a direct short.  It is a current leak to ground or another circuit that is overheating the fuse.  See if any filaments are lit up that should not be or that are dimmer than expected.  Might be a clue.

[240zadmire]

4 hours ago, Zed Head said:

  It is a current leak to ground or another circuit that is overheating the fuse

I would never know this.  🙂

 

I’ve been driving the car almost daily and every few days, I needed to replace the fuse.

 

will check again tonight to see what wrong.

 

stay tune.  Live and learn new thing everyday 🙂

 

[Zed Head]

Actually, it might be a direct short that only happens every few days.  Second-guessing myself...

Touch the fuse after driving for a while and see how hot it is.  Be careful, it might be really hot.  That will be a clue if it's a fuse on the edge of melting that finally does after a few days, or if it's a sudden direct short.

[Captain Obvious]

I'm lost... What's a "signal fuse"?

[240zadmire]

1 hour ago, Captain Obvious said:

I'm lost... What's a "signal fuse"?

When I took the driving test, the proctor asked how to use hand signal to turn left, right... that was 100 years ago.  I've been using hand signals lately.   Hopefully other drivers don't get offended and mistaken that I gave them the middle finger, especially turning right 😉

I bet gen XYZ don't even understand what is the meaning of roll down the windows let alone use hand signals. hahahahahaha 

It's the flasher 10A fuse for the left, right turn.  You pulling my legs!!!! glad you pay attention to the details.

 

[240zadmire]

Took all bulbs, clean and examine each socket ... nothing ordinary that I can see.  No fog or hazy.  No warm feel at the fuses box.

Been driving couple of weeks and put couple of 100 miles on it.  it is not blowing anymore.

One thing I didn't mentioned was that I do not have radio currently install.  There are some wires with copper exposure that I didn't tape it cleanly.  Possibility could be one of those wire touched the metal that cause a short.  I've cut and electrical tape those wire cleanly.  Hopefully that was the reason.

 

[240zadmire]

Arggg spoke too early…. Took the car out for lunch.  Switch on AC, engage left turn signal, and poof, fuse blown again.  Wonder if something short in the AC electrical path/switching lever… 

[Zed Head]

AC has its own fuse.

[Zed Head]

Check the back of the fuse box.  Fuses blow from heat.  Maybe you have some corrosion, causing heat, or a short circuit to the AC circuit.  

[240zadmire]

you're on to something!  I think the fuse blown during the hot days, lunch time frame.  I'm not kidding.  The tiny cabin with black interior IS really hot when during lunch time.  This is really interesting to know the hot weather and the current rush in cause this phenomenon.   Will have to unscrew the fuse block/box later.

[Dave WM]

did you take the multi switch apart to clean it?