Omg please help... Engine fuse keeps blowing... WHY!!!!!??????!!!!!!!!??????

[T4Mike]

1986 t4r

A couple months ago my engine fuse blew. I changed it. Ran fine.
A couple weeks later, it blows again... I replace it and wonder why and start driving again. Blows again. Replace it... Take off, blows again. 5 times it blew. Next day it ran fine. Few days later, same thing... It blew 5-6 times. Back to back...
When the fuse blows, the charge light comes on, I lose dash gauges, and it loses power when trying to accelerate.

I took it to the shop to get AAL installed, heater core, a.c. evaporator, idle adjusted, header install, and to check on this engine fuse deal. Well, of course... The entire time they can get the fuse to blow. So I pick it up today... It's running great. I'm so happy. Few miles from the so... The fuse blows. 5 times I had to change it to get home. The last time it blew... I pulled over to change it. Turned the truck on, turned my headlights on and made it home no problem. Got home and sat and idled. Revved it up a few times... No problem. I turned the headlights off, revved it up, the fuse blew again.

This is about to drive me crazy. New battery. New alternator. I checked the ground wires, all good. I seriously hope someone has an answer for this.

 

[fourwd1]

There are some wires that cross over the valve cover that tend to wear through the insulation and cause intermittent short like you describe.
Inspect them closely.

 

[RAD4Runner]

Back-up light switch and 4WD indicator switches could also rub against tranny/transfer case.

See illustrated post here.

 

[T4Mike]

I remember actually reading that somewhere also RAD4Runner. I'm about to start digging in now. I'm replacing the headlights (H4 conversion) and wire harnesses. Also putting in all clear lenses and all new bulbs. So I'll be testing all those wires as well. When I use the left blinker, it seems to draw power and the dash lights dim as it flashes.

 

[ltsr]

Also check the o2 sensor wiring, if they are chewed up and touching they would also exhibit the same behavior.

 

[RAD4Runner]

I'm replacing the headlights (H4 conversion) and wire harnesses...

Do the harness first IF could only do one thing at a time. It is more essential. See explanation on my thread.

When I use the left blinker, it seems to draw power and the dash lights dim as it flashes.

Sounds typical of flasher/hazard. In my case, when I have parking brake on, flashers/hazards dim the brake indicator light, too.

I haven't tested whether it's the relay or the bulbs that do it.