the best learned lessons are often the hardest ...

recently ripped out practically the entire interior in my xj in preparation for a roll cage, while I was at it decided to rewire (battery is in the back, lots of messy wires that needed to be cleaned up).

Got everything re-connected and working , but for the life of me couldn't get the fuel pump to turn on. I'm running a terminator EFI on my 350, and had wired a safety switch between the EFI unit and the fuel pump relay. I tried everything.. ripped out all the trim so I could trace all the wires from the EFI to the fuel pump, triple tested the wires, replaced the relay, pulled every fuse. Gave up to leave it until tomorrow... and then realized... the fuel pump doesn't turn on unless the switch AND ignition is on.

Lesson learned -- the simplest solution is typically the answer, and even if it isn't, it's a good place to start. three hours of my life I'll never get back.

We've all been there!

On the same note -- 2000 XJ power door locks

I spent a few hours tracing wires and testing switches trying to figure out why only sometimes my door would lock with the switch -- finally figured out that they won't lock with the key in the ignition -- I feel your pain...

and I made it even worse... turn on the key, fuse pops. replace, check wires, turn on key, fuse pops. Took me two hours to realize that as I was tracing wires, I plugged the fuel pump under the truck into the wire harness in reverse.... power was connecting to a ground.

time to pack it in again, let it sit till the morning... making way too many stupid mistakes.

Yup. Heading to an event in November my truck showed me no trailer brake connection. I spent 4 hours ripping all of the wiring out of the trailer and rewiring the entire thing, and then a second time, with no success - only to find that the 20" wiring extension for my hitch extension had become unplugged from my truck. Trailer was plugged in just fine, to an extension cord that wasn't plugged into anything..

Just last week I spent several hours testing components and and fuel pressure only to discover I had the flipped the pressure and return hoses at the pump.