So trying to diagnose why my battery wasn't charging finally led me to the fuse block on the driver's side kick panel

Lightly pushing sideways on the whole block directly affects if the battery is charging or not. Pushing on it a little more seems to cause loss of power to the battery, which returns when i release pressure. I'm guessing it's just one wire, harness, or relay that's loose/damaged that would cause these symptoms, but which is it?

 

That's quite odd. The best thing to do is check all connections around the fuse block first.

 

What does that mean? Are you measuring something (voltage? State of charge?) at the battery?

If the voltage at the battery drops when you press on anything (but certainly the fuse block), it means you're shorting 12v to ground somewhere. Be careful; shorting a truck battery to ground can produce one helluva fire!

 

I would bet some of your fuses are loose in the block sometimes the female side gets loose after a while .

Figure out just what one is part of the charging circuit and go from there.

 

Like 93Xtra-Cab, Scope and Wyoming said ^^.

Where are you measuring voltage? At battery posts? After battery Connector?

Inspect for dirty or loose connections, corroded crimps, shorts, damaged wires, etc.

What year and model do you ave so people can help you with schematic?

 

It's a 93 pickup. i'm just looking at the battery gauge. it goes from just over a half to just over 3/4 and vice versa when lightly pushing on the block. i only noticed once the battery light come on, and that was yesterday when it was reading just over half and my typical quick fix is to push on the block a bit until it returns to normal, but that time i pushed a little too hard i guess and the battery light came on, but when i released it, it went back to normal

 

So you are not really sure of your battery voltage?
Best to see schematic of your charging system and what fuses are on that Fuse Block.

However, right now (basing on schematic of a 22RE) my guess is you have poor connection that interrupts power to "IG" input of your alternator. This is usually a thin red wire. This should have 12V when ignition switch is on. It takes 12V from Engine Fuse, IF your truck has same circuit as 22RE. That's why it's important to have schematic. When you lose 12V here:
1) Alternator output will drop and show as low charge on gauge,
2) Alternator "L" output (thin yellow wire) will go low, and ground negative side of your charge error light making it go on.

So bottom line is, no matter the theory behind your problem:
1) Check all fuses and connections in and around fuse block
2) Get a multi-meter if you don't have one- best to measure actual voltage than to rely on rough alt/charge gauge.
3) Find schematic for your truck
4) Label all wires, in case any of them comes off

If it would help you understand, below is a basic charging circuit (22RE). This is a robust circuit so it should not change much from one model to another.

Start by checking "IG" (red) wire to make sure it is reliably getting power from Engine switch to connector on alternator.
With engine off, disconnect connector (not post) of alternator
Multi-meter on Volts DC, 20 Volt max setting.
Red probe on IG pin, black probe on battery negative or bare metal of body.
Turn ignition on - but do not start
You should get 12V at IG.
Have someone disturb fuse block wiring and see if you lose 12V at IG.

Also do same with "S" (thin white wire). This actually taps off the main thick alt-to-batt wire near fuse block, but is less of a suspect for me.

Report back.

 

I had this exact problem for about a year on my 90 4runner (22re). Changed the alternator about three times before I found it by accidentally pressing my foot against the kick panel. I removed the fuse block and found no issues. I then re installed it and never saw the problem again, my guess was one of the connections to the block was loose and needed just to be connected properly.