Rep Power: 0

I've looked and please don't spam me with noob post or anything. I really need help. My buddy has a 96 Civic with a B18 and we just finished putting the new transmission in. Everything ran just fine until his roommate drove it into the backyard. First the battery ended up draining bad for sitting about 2 weeks with the door cracked open, so we replaced it. And still wont start, I thought well starter relay since it was going nuts, swapped and nothing. Now I'm either thinking the main relay by the glove box so ordered it last night. My issue I'm having is you turn the key and on acc you have power to everything like normal and can even hear the fuel pump and everything. But moment you clutch in and turn ignition to start position we lose all power to everything, every now and again you'll hear the main relay click outta control but not every time. Anyone have an idea for me before I start just rewiring everything I can think of. Thank yall alot I try not to bug people with me mechanical stupidity but this is getting frustrating.

 
Rep Power: 518

Poor connections at the battery, battery clamps and cables, or grounding points.
Or a junk battery.

Voltage drop testing could pinpoint the source of the problem.

 
Rep Power: 0

I'll try checking all the grounds and the battery terminals again. And the voltage test was good with a load. I just didn't know if I'm maybe missing a fuse or maybe a wire that mighta got pulled by the clutch pedal. Thank you again ezone

 
Rep Power: 518

If you only load tested the battery, that doesn't load the entire system.

Something (in the battery main circuits) is going 'open circuit' under the load placed by the starter.

 
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I did the voltage load test and couldn't find anything. I was thinking maybe the clutch safety switch but it looked alright. I'm just dumbfounded and really starting to get irritated

 
Rep Power: 518

Quote:

we lose all power to everything

This means the dash goes dead, the headlights are dead, no horn, no hazard lights, right?