Short to ground?

[farrartruck]

Hi,
I recently rebuilt the throttle body on my 87 R10. It was my grandfather's truck that my grandmother sold me a few years after he died. After rebuilding the throttle body it ran and drove great. Battery was dead when I first bought the truck (it had been sitting for a year and a half). Battery was replaced, I tested for a parasitic load, and the it was only pulling about 16mA when turned off. I left the battery hooked up over night after the throttle body rebuild and the next morning nothing worked but the dome lights. Tried jumping the truck off and nothing happened. Battery was reading about 12.55 V on my meter, so pretty close to a full charge. Went and got it charged anyways and tried it again yesterday, upon trying to start the truck, the radio and all electronics blinked to life, but before it could turn over it all died again and my battery (which was at 12.7V after charging) dropped immediately to 12.66V. Battery seems good to me every time I measure it, and it seems like a short to ground somewhere. The weird thing is that there are no blown fuses. Anyone have any ideas on where to start trouble shooting? Or any good literature for schematics? Pic for attention.

 

[wanderinthru]

Grounds, clean the grounds, all of them. With things turning off and coming back sounds like a dirty ground.

 

[Bextreme04]

Yep, grounds and also look at the ignition switch wiring.

 

[SirRobyn0]

I've also seen where corrosion will build up in the side post. The bolt will still make good contact with the battery but the cable not so much. You might check that, and then hit the grounds.

 

[farrartruck]

I tried cleaning the grounds and battery terminals and no results. I'm going to give that ignition starter switch a try next. Seems to be the most likely culprit because headlights and dome lights work, and to my knowledge everything else (except the dash clock) are activated by that switch. I appreciate all the help

 

[75gmck25]

FYI - ignition switch on/off power wiring runs to a switch on the lower column and that is where the electrical is switched. The key switch just turns a toothed metal “rack” and that pulls/pushes a rod running down the column. The rod is connected to the electrical switch.

The point of my explanation is that you might have a broken ignition rack at the key (very cheap part, PIA to replace) that is not moving the rod properly, or the switch mounted on the lower column might be out of adjustment.
This is an example of what the rack looks like.

Advance Auto Parts - Down for Maintenance

 

[Rusty Nail]

There was that one dude that broke his new truck switching LED bulbs. I'm pretty certain the DOME LIGHT was the culprit - outside of LED bulbs lmao
Might wanna check with that guy.
I get you havent caused problems with modern tech in a classic truck , but he WAS having dome light problems that kilt his batrey.


Hay. U member that one guy?

 

[Ricko1966]

Clean your positive lead at the starter make sure the main battery ground is to the block or cylinder head.Short the solenoid at the starter that will tell us a lot. Short big terminal to little terminal with a screwdriver I use a quarter but everyone else use a screwdriver. If it cranks when you short it,that rules out starter,battery,and cables. A short to ground would result in a burnt fuse, a burnt wire or a burnt fusible link. I just reread your original post sure sounds like a dirty connection to me.
.

 

[Rusty Nail]

Just seen Nov 8.

 

[Ricko1966]

Just seen Nov 8.

Lol I keep falling into this old freaking thread trap. Sorry

 

[Scott91370]

Lol I keep falling into this old freaking thread trap. Sorry

You start reading a bunch and before you know it you're 40 pages into the section on a thread from 3 years ago. Happens.

 

[Rusty Nail]

I love it! Topping old threads is /win!

Danged ol LED dome light guys!