WE are stumped brake fuse over heating

[Ericster]

hey guys i need help again. my brake fuse keeps melting my fuse block the brake light work and all but the fuse overheats. Also my rear turn signals dont work the front ones do and the light comes on on the dash but no rear light. checked all the bulbs there good. so are these problems related and does any one know how to fix them?

[Ttiger]

I'd start by checking all the wiring at the tail lights. Especially the plugs and the bulb sockets for corrision while you're there. They are easy to get to and may be a part of your problem.

The brake lights are on a separate 20 amp fuse (240Z) so it would take a huge amount of resistance to heat up enough to melt the fuse.

[Mikes Z car]

My brake fuse has also melted the fuse block, not sure this is a recent thing just noticed it today. Elsewhere on this site I remember a solution of soldering the thing the wire is crimped to to the fuse holder after pulling the fuse holder out of the fuse block temporarily or something similar. The idea being corrosion between the two metals caused too much resistance and hence the heating.

[Ericster]

ill check the corrision get back to you guys if it fixes it

[Ericster]

nope couldnt find any corrision

[geezer]

nope couldnt find any corrision

From the times shown on your last two posts, I don't see how you could have possibly found anything. You have been steered in the right direction. Taking the suggestions seriously is the only way you will find the problem. High resistance due to corroded wiring and connections is most always the cause of overheating and melted wiring.

[Ericster]

i get what you mean about the times but ive been cleaning connections for over two years and worked on this one problem for a couple weeks me and my dad checked the bulbs and all the wires to the fuse block and the wires to the switchs again. couldnt find any corrosion.

[geezer]

i get what you mean about the times but ive been cleaning connections for over two years and worked on this one problem for a couple weeks me and my dad checked the bulbs and all the wires to the fuse block and the wires to the switchs again. couldnt find any corrosion.

Ah I see. Maybe the best thing to do, to hunt down a problem like this is get a wiring diagram and a multimeter to check the resistance of the circuit or find possible shorts to ground or bad/weak grounds.

[Mikes Z car]

I went out to solder my fuse block to stop the melting of the fuse block

(How did I get off on this? Aren't I working on rust prevention? But the fuse block was right there with everything removed, and while I was at it...)

and I think I noticed what may be hiding here assuming I understand the discussion. I made the rash assumption that all one had to do was solder the rivet to the bus bar (see attached annotated picture -not sure I used the right terms) but on closer inspection (someone chime in if they see this differently) there are three connections here, the wire to the crimp, the crimp to the rivet and the rivet to the fuse holder as the rivet is a separate part. If I solder the rivet to the bus bar and the connection that is high resistance is between the rivet and the fuse holder I haven't accomplished anything. I notice others have put in separate inline fuses to bypass the hot connections to solve this. I may try soldering a 14 gauge wire from the fuse holder to the bus bar but that looks tricky to me due to the limited space.

[jwtaylor]

You just need to solder the Fuse holder portion to the bus bar. If you get it hot enough and use a good flux the solder will be pulled into the space between the parts. You could also heat the top of the rivet and flow a little solder around its head as a little extra protection. Use a good electronics rosin core solder or a electronics flux and solder. Stay away from acid based fluxes!

I did mine about 10 years ago and had not had any more problems with fuse heating.

[Unkle]

There's a member here that makes improved complete wiring harnesses for your car( just the tailight end if that's all that's needed) . Get rid of the near 40 year old crap and put his on . Also MSA has modern plug and play fuseblock assemblies using new style fuses . Go that route and your issues ( electrical ) will be solved.

Edited July 13, 2009 by Unkle

[Mikes Z car]

jwtaylor,

Very good I didn't think of soldering there between the fuse holder and the bus bar, I will give that a try first, much easier than my idea.

Unkle,

It looks like the MSA 240Z replacement fuse box uses rivets? I guess even if it uses them and it is new it should work for some years.

Almost feel I partially hijacked this thread, all due apologies to the thread starter, hope you have benefited from the info.

Mike