Thank you for posting your follow-up. It is of immeasurable help to others. Far too many will leave their post hanging and we cannot get confirmation that a fix solved the problem.

 

My '05 Jimmy did the ba da da...dats all folks, on a radom nice day a few weeks ago.
I was not home...thankfully it died on a friends driveway only 538 KM from home, and I was welcome to stay while awaiting a new fuel pump.
Dropped tank, buddy says power power at the connection...we order pump.
Pump comes(northern Ontario) and installed same crank no start, check no power at pump connection...check ground...great ohm result.
While I am there, I wire an "emergency wire" to the fuel pump connector and run the length of truck, did not connect to anything.
The next morning do out and start the truck..the crank no start seems to have resolved...drive the truck randomly for the next day everything seems to be fine.
Leave friends place and within 5 minutes truck quits, crank no start, no fuel pressure, no hmmm from gas tank. drill hole in top of UH fuse box, connect wire to(what was the fuel pump relay) the headlight relay. Turn on lights, pump humms crank and start. Get to my camp some 90 km away. I have been having a "ignition key problem" wiggle it to get it to turn which became "intolerable" during this trip. Aftermarket BT radio unit winking in and out, I figure ignition switch, get a chev column for half the price of a ignition switch (brought up from the Ol US of A) My my, had to name that "what F'ery is this? not the column, the wiring attached to mine. Old remote, security system? Anyway a security relearn and still a crank no start, key works fine, BT radio fine, I drive home with emergency wire to headlight switch. About to go out and try that putting power to that port and see if it "HUMMS" and if not run a continuity test (disconnect battery) between emergeny wire and term 87(thanks petty fog for schematic!)...looked under fuse box when in north seen no burn and checked(several times) ecm b fuse. hoping not to have to go buy a bootom end fuse box....great forum guys!

 

This needs a new thread because it caught the original thread on fire. Some Blazer forum humor.

I'm not sure I am tracking all of this. Some questions:

1) So without a jumper wire there is never any power to the fuel pump?

2) Why did you jumper from the headlamp relay, is there something wrong with the fuel pump relay or its socket?

3) How does the ignition switch fit into this? Was that only a mechanical key problem in the lock cylinder or was there voltage problems? If voltage problems where and is that fixed now?

4) Why did you need a security relearn, did you replace the passlock module or do the resistor hack?

5) Does the truck always run OK with the headlamp relay hack?

6) When you have a crank no start do you have spark?

7) What brand of fuel pump did you put in?


George