Blowing 10amp tail and parking fuse

[Vince V]

Over the weekend was out driving at night and after about half and hour the tail/ parking, directional and dash lights went out. Checked the fuses and the 10amp park/tail light fuse had blow. Replaced the fuse and made it home.
This morning I am trying to diagnose the issue.
When I turn the car on I notice that the tail/park fuse begins to get progressively hotter , I did not let it blow out.
Also noticed that the horn fuse begins to heat up. Unplugged the horns and no heat. Should note that I have a 67.5 wheel on the car and do not have
a functioning horn.
All the other fuses do not get hot.

I am not very good with electrical, so any thoughts would be appreciated and how to go about finding the problem.

Vince

[fj20spl311]

One common problem is a bad connection at the fuse holder rivet. The fuse should not get hot to the touch.

[Gars68]

Corrosion causes resistance so I would clean the connectors with electrical spray cleaner and some emery cloth. I'd pull a few tail lights and inspect/clean there too as this is a common place for corrosion. Gar

[Vince V]

Thanks,
Already pulled the tail and front parking lights and all was good. No corrosion. Cleaned them anyway.

Just picked up all your responses. Will take a look at the fuse block.

[notoptoy]

Diito What he ^ said.
From Scott Scheeler's book "All headlight fuse circuits on 68-69's go bad, best remedy is replace the fuse block." While the statement is true, I believe the rivet can be addressed by re-work if not to far gone. Otherwise, the replacement fuse block will also go bad in 20-30 years or so.

[Mainer311]

The fuse block can be repaired by sanding the rivet and fuse contact, then soldering.

[Vince V]

Well you guys nailed it. Pulled the fuse block tonight and the right side ( assume hot side) of fuse holder for the tail/parking fuse is discolored and actually started to melt a bit of the plastic. Its very loose, but that may be from the slight bit of melt.
I have a fuse block from a parts car which I will replace over the next weekend.
Hoping the fuse holder was the issue and not something else that created the heat in that fuse contact.
Thanks all
Will report back when I make the change.
Vince

[notoptoy]

Check out, and make sure all rivets are tight and corrosion free on the replacement fuse box prior to installing or you'll be doing it again in a short while!

[Vince V]

Quick update.
Today ( in the day light) I was able to take a close look at the fuse block and the rivet for the fuse holder that is heating up. . The rivet looks okay, and is just as tight as the other rivets for the other fuse holders.
I am thinking that something else must be creating the heat.
Also, My plastic fuse cover and my original owners manual show the park/tail light fuse as 10amp . The wiring diagram in the tech wiki shows it as 20amp any one know the correct fuse size?
So, would a bad light switch or possibly the head light rely come into play? grasping fro straws.

[fj20spl311]

I can be caused by the prongs for the fuse not being tight.

Best to get a ATO fuse box, Curtis had some conversions.

[Mainer311]

+1 for ATO fuse block conversion. I did it and haven't looked back.

[car_cursed]

I kept blowing the headlight fuse on mine. I cleaned the contacts and have not had a problem with. I think that was already suggested, but not sure if it was executed.

[C.Costine]

The heat and melting at the fuse box is a very strong indicator of a problem there. Another possibility is a wire terminal that is loose with corrosion. The corrosion can be hidden under the terminal or under the wire insulation.

[sunbeam590]

I had the same problem, went on for months, finally after checking all connections and about 5hrs work it turned out to be the dash lights dimmer switch, so I just connected the in and out wires together (spade connectors) behind switch, that was over a yr ago no more troubles since , worth checking, pull the connectors off and see if it still heats up ...cheers .

[Vince V]

Update;
I changed out the fuse box over the weekend. In addition , I cleaned every bulb socket, connection and all the grounds.
The park/light fuse has not blow with the lights on , but it does get warm. Warm to the touch , but not burning hot as with the old fuse box.
I would assume since there is current going through the fuse and holder that it would get a bit warm.
I also disconnected the dash light dimmer switch some of you have suggested.
Any thoughts would be appreciated.
Vince