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The horn button on my '79 was loose and I decided to adjust the fit so it wouldn't vibrate. As I attempted to re-install the horn button the noise of horn was irritating, so I disconnected the leads to both horns. As i pressed the horn button onto the wheel, I could hear the horn relay clicking and clicking. After I was satisfied with the snug fit of the horn button, I reconnected the leads to both horns and tried the horn, but there was no toot. I know the fuse for the horn is the same circuit as the courtesy lights and clock and they were both working, so I figured it was probably the horn relay. I went to NAPA and got a new relay and put off replacing it till the fall weather kicked in.
Today I removed the driver seat and crawled under the dash and I noticed the plastic of a fuse on the carpet under the fuse panel. The plastic at the rear of the fuse body was melted, but the metal fuse portion was still in the fuse panel, that's why the clock and lights were still working. I disconnected the negative battery terminal and pulled the metal part from the fuse panel and the links were still connected and not blown! The plastic around that fuse was melted! I pulled out melted plastic so I could fit another fuse in there. Still no horn. Then I looked up and saw the totally melted horn relay and socket hanging next to the fuse panel! I had to cut the wires to remove the melted socket and relay! I have ordered a replacement socket and will have to solder it or use crimps to the cut wires when I receive the new socket.
The bottom line is this: a CHEAP Chinese fuse purchased in a large box of fuses at Harbor Freight could have possibly caused my car to burn up!! I have discarded the Harbor Freight fuses and I encourage everyone to NEVER USE cheap CHINESE fuses!
Last edited by JagNorb; 11-12-2018 at 09:00 PM.
Reason: Added photo
I would have to agree that 30a fuse is rather large for the circuit.
I would also have to say there was a heavy current draw to melt the insulation on the wires and to melt the relay holder, and to melt the fuse plastic.
Is it possible that the horn connectors were shorted to ground while you were working on the horn button?
The fuse should have tripped, but a 30a rating is a lot of juice.
W-crimp pliers work perfect for crimping new terminals to the harness and give you a clean looking install for the relay holder.
Might want to take a look at the rest of the circuit to make sure you don't have anymore damaged wire between the relay and horn.
11-12-2018, 08:38 PM
Failed Cheap Fuse could have lost car!
glad you didnt burn the car down.