No sir, you can man handle the hell out of that extra weight to your hearts content. You said five gallons right? So about 45 extra pounds is all. Twice I have had a fuel pump fail in a full tank, once in my truck and once in the Blazer, so near 18gl and 30gl.

 

How can I be sure it's not the relay?

 

look at the relay on the firewall,the one right beside it is for the ac. Its the exact same relay. swap em out and if she starts and the ac doesnt,boooya! just the relay.

 

Tried that and no action. What if I have 2 bad relays ?

 

does your compressor kick on when you turn on your ac?

 

It use to when it was running. I do here like a click/thud under the hood when turning on the ignition to the run position.

Sounds like some relay or something.

I guess I'm going to face the truth that it is more then likely the fuel pump

 

have someone place there hand on the fuel relay when you turn the key. if they dont feel anything,replace it. besides,you need to replace the relay with a new pump anyways just for insurance.

 

Is the fuel pump relay the one on the left or right while standing in front of the truck looking at the two?
Thanks.

 

Sounds like your best bet is goin in to autozone, or your choice dealer, and grab a manual on your rig, the pump, filter, and relay, petrolium gelly, dialectric grease, and go home. Do some reading. and fix it. That or its mechanic>scrap..