96 3.4l 150,000
4runner

Good story. A deer took out my front left turn signal housing, so I removed it. shortly after massive sparks flew drum under the hood. My guess is the air draft blew the battery retaining strap over onto the positive terminal. I quickly pulled over and shut it off but the terminal was melted... in the dark with no cell reception on a back road, I decided to try and get it going sgain.

I got my positive wires re attached, and the truck started. I was in disbelief it ran, but, whenever I hit a bump, the gauges, radio, and lights would dim. Speedometer needle drops etc. it progressed to get worse, and now the motor won’t stay running. I’m very mechanically able and a decent shade tree... but this is baffling me...

Seems like the fusible links (wires under the hood fuse box in clear plastic) are fine. I am not seeing any burnt wires. Thanks!

Hmm... The impact with the deer or the air draft?

Did you see evidence that the battery hold-down clamp was actually what shorted?
If it is indeed the battery hold-down clamps that shorted to battery positive, then most likely your fusible link will be OK because they are outside the short loop caused by the hold-down clamp.
The short is more likely to have affected the ground circuit OR internal part of your battery.
So I suggest you:
1) Have battery tested,
2) Inspect battery to ground connections, but still double-check the positive side. Most likely to be affected by the short you described would be battery negative to fender ground. That was the path of least resistance for current during that event. That also happens to be the ground path for engine control and critical electronics.
3) Don't just look. Electrons are hard to see. Need a multi-meter to check wiring.

Thanks for your thoughts!

Yes I am Sure it was the retaining strap on the positive terminal. By the time to slow, pull over, open the hood and knock it off the terminal it had been grounding for a while.

Last night I tried a different battery with new terminals and symptoms persist. I also followed the ground wire to the block and didn’t see anything weird Maybe there could be non-visible issues.

Interesting about the fender ground.. I hadn’t have that Connected for a long time since it wouldn’t reach my battery. Maybe there is something to that?

I dont understand why movement and vibrations cause the problem buteverything is fine if not moving

thanks

That's how most electronics are grounded. The shorting event is a perfect example of why people preach "check your grounds". It is rather unpredictable which path current from a dead short would take.

I’ve done quite a lot of maintenance on the truck, purchased as is for $300, I’ve done everything from fluids, welding the frame, front end, bearings, brakes, etc. electrical hasn’t been my cup of tea yet. I learn a lot from forums.

Ok so with shaming aside, ideas on solution diagnostics? Seems like you’d have some specific suggestions. Thanks

Good stuff! Thanks. I’ll look into it asap