Parasitic Drain on battery power and other electrical problems.

Hello Folks, I am trying to run down a parasitic drain on a 2001 Yukon.
I discovered it when the dash lights, the fuel pump and code reader
stopped working, I know pump and dash lights at same time.
I have cleaned all grounds except the main, it appears to be clean.
I checked all fuses then tested each circuit with a meter in the positive line and pulling the fuses and checking if the 12.4 vlt drain had stopped when I did it, same thing to all the resistors, I did it twice, I can't stop the drain by pulling fuses and relays. So I cant find it. Are the underhood and driver side door fuse boxes the only ones on the truck? I can't find any others.
I have changed out the fusible link wire on the alternator, changed the headlight and dimmer switch assembly. Nothing has helped.
It will crank but won't start, the fuel pump, which was installed at a shop new three weeks before this happened, is not coming on. Some suggested the only place that all those wires come together is in the ignition switch.
I am at a loss as to where to go from here.
Any advice to move forward solving this greatly appreciated.
Benny

So you have 2 problems as I understand your post (which is kinda hard to read because of the returns at the beginning...)

1. Cranks but doesn't fire.

2. Parasitic battery drains.

Regarding problem 1: you mentioned the fuel pump doesn't prime. Figure out why not. FP relay okay? Go down there near the tank and start checking if you have power and ground. If one is missing, figure out why.

Problem 2: which is the fuse that's drawing the battery? You need to either check with a DVOM with the circuit in-line to measure amp draw or check with voltage drop. Do this on each fuse to see which is the "bad" one. Then find a wiring diagram to see what that circuit feeds and start disconnecting switches or modules until you find the culprit.

Don't use the "pull the fuses" method, since it can wake up modules during the test; there's an easier way. There are lots of good YouTube videos on diagnosing parasitic draw. Here's one:

strutaeng said:

So you have 2 problems as I understand your post (which is kinda hard to read because of the returns at the beginning...)

1. Cranks but doesn't fire.

2. Parasitic battery drains.

Regarding problem 1: you mentioned the fuel pump doesn't prime. Figure out why not. FP relay okay? Go down there near the tank and start checking if you have power and ground. If one is missing, figure out why.

Problem 2: which is the fuse that's drawing the battery? You need to either check with a DVOM with the circuit in-line to measure amp draw or check with voltage drop. Do this on each fuse to see which is the "bad" one. Then find a wiring diagram to see what that circuit feeds and start disconnecting switches or modules until you find the culprit.

Click to expand...

The fuel pump is not getting power, neither are the dash lights, the code reader and I don't know what else. Crank no start over no power to fuel pump.
Checked the relay and rechecked all the fuses looking at amps.
Fuses look fine. Cannot understand what is going on here.