Still burning thru Fusible Link......

[Marblehead]

Still burning thru Fusible Link

I’ve searched, read and performed all the upgrades but still slowly burn thru the Fusible Link 1.0.

’83 with 6M and higher output Camry alternator with necessary diode jumper installed in the kick-panel fuse box. All grounds have been upgraded to 6-8 gauge wire (4 years ago), alternator-to-battery wire has been upgraded to 4 gauge and fused (one year ago), no stereo upgrades or large power draws.

Over the years I noticed both of the fusible link wires were hardened and associated that with age and heat cycling. A year ago I experienced a few electronic hiccups over the course of a couple weeks then the car died on a drive home from work. I knew the source immediately, jiggled the fusible link wire and made it home. I replaced both the larger, 1.0 link and the smaller 0.3 link with OEM from Toyota. At that time I also upgraded the alternator-to-battery wire after reading that may be the culprit to the fusible link running hot. A couple days ago, similar experience. Radio went in and out a few times before everything dropped out for a brief second: tach dropped to 0, clock reset, etc. I carry a pack of link wires in the glove box. The wire replaced a year ago had melted the insulation at the female spade and the receptacle on the fuse block is slightly bulged from heat cycling. Mind you, the fusible link does not pop/blow. Rather, it has slowly hardened and weakened due to high heat cycling. This time after only a year.

Now I’m stumped as to why there continues to be so much heat running thru that fusible link. Any thoughts or additional findings from others? Any and all assistance is appreciated.

Picture 1: Fuse block with new wire installed. Shows deformed receptacle.



Picture 2 & 3: TOP - small Fusible Link 0.3 (original), MIDDLE – Original Fusible Link 1.0 which was replaced l year ago. Wire was as hard as a stick. BOTTOM - Fusible Link 1.0 after only 1 year of use.





Electric lady land,
Scott

[lacrssgus14]

starting at the top.

The power feed to the voltage regulator goes through that FL.

The power for the wiper fuse goes through that FL, via the ignition main relay.

The power for the fog lights goes through that FL.

The power for the A/C condenser fan motor through that FL, via the condenser fan relay.

The power for the stop lamps is through the FL

The power for the headlight cleaner motor is through that FL.

And finally the taillights are powered through that FL


Time to get out a meter and start turning systems on and off until you find the high draw.

Good luck.

Edit:

Does the 4ga alt. Feed wire run direct to the battery or through the blue fusible link in the black box like factory?

[Supradad]

Check the under side of your black fuse box, where those F/L spade connectors attach.
Those connectors have got to have heat damage too.

[Marblehead]

starting at the top.
The power feed to the voltage regulator goes through that FL.
The power for the wiper fuse goes through that FL, via the ignition main relay.
Edit:
Does the 4ga alt. Feed wire run direct to the battery or through the blue fusible link in the black box like factory?

Oh boy. Time to get looking. Thanks. The 4g from alt to battery runs direct. The intention was to create a clean route with the least amount of resistance. According to an option I read in a post last year when the first FL was killed. On the AC fan - I installed the Jim King AC kit about 6 years ago.

I have an electrical TSRM but not currently at home. Do you, by chance, know the current flow direction thru the FL? Does it travel front-to-back or back-to-front? Both burning FL were damaged at the rear spade – as shown in the pics.

[Marblehead]

Check the under side of your black fuse box, where those F/L spade connectors attach.
Those connectors have got to have heat damage too.

Thanks! Yup, that is already on for this weekend along with checking the resistance of those wires. Wonder if they've become so hard from the previous problem that resistance has increased thus causing this recent heat.

[Solo1Supra]

Poor/corroded grounds will cause excess current draw as well.