We took our 98 GMC Z71 pickup to mechanic to replace the fuel pump?

I've done this job, wither the bed comes off or the tank comes down. I wouldn't unhook the battery either. But that's not the point. If the fire originated from the back where the tank was then it's going to be on them. If not then it's not. If you change the pump and the truck runs then mission sucess. Even if they went under the hood they would simply be hooking to a Schrader valve with a pressure gauge. Perhaps it was a missed diagnosed fuel pump? Perhaps it had a leak somewhere causing the issue? No telling but this is why there is insurance. For both you and their part

Ok...so you don't have to remove a fuel line or do a pressure test to install a fuel pump on this type vehicle? By the way it has (had :( ) a 350 Vortek engine

A fuel line doesn't need to be disconnected to test pressure but it is under the hood. And Mr. "I disconnect the battery to change a headlight." Please enlighten me, what sensor will I burn up doing this job? No power gets to the fuel pump harness with the key off, or the sending unit. The "disconnect the battery" rule is there for uncertainty. If you don't know the system it is in your best interest to disconnect it. I can tell you right now, to do this job it isn't nesessary. If you still think you need to do so for this repair it just proves you don't know what your talking about.

Btw I'm not defending said shop, I'm just trying to educate. If this goes to court the easiest way to lose is to sound like and idiot. You won't be taken seriously. If your opening statement is "he had to open the hood to disconnect the battery" then your going to look like a fool.

Are you saying that a short in the system could not be an issue.

Your the only one calling others names just shows your level. Key on or not a short can be anywhere. If its positive to frame then it can go threw any ground into any systems wiring.

We are talking about the fuel system not a headlight. I do not unhook the battery for headlight myself.

The rule is there for protection.

Main thing is it happened at their business.

Everybody know about parasitic battery drain, The power loss ends up at the frame or body. You work the way you want to work and I will do the same here. Can tell you this if they do go to Court it look better for the shop if they did recheck their work and tested the entire fuel system and disconnected the battery while they did the pump. If they never popped the hood they cannot say they did either so who is the Idiot. The owner who trusted the shop to fix their truck or the shop Owner & his employees. Anyone who goes to a shop is expecting that that shop will not let them leave from there with a safety issue, It caught on fire and burned to the ground, For crying out load how can you sit back and act like they the owners or I are idiots. They trusted the shop It is a public business, they have reasonable justification. Your too little to be belittled.

By looking at your picture your less than a third my age. I have been wrenching on more than cars and trucks since I was a child. I know more than you ever know even if you could grow a beard down to your toes. Wisdom is common sense compiled over years. Taken Seriously you say, It Happen after they worked on it, It happened at their business. The Business owner was no where around when they came to pick it up to let them sign off on his work. Its their fault. All the truck owners have to do is sue and if they loose the first time appeal until it goes to Jury/and they will win when they are in front of a Jury.

We do not know what shop did or did not do so if the shop is not helping you and going to help you then make them tell the court or lie to the court. They offer a service to the public, they should be standing behind their work. Have a fire investigator or another shop look at your truck for the truth behind the fire or anything that was left undone or improperly done. You may even be able to see where it started yourself and take pictures it too.

You cannot take the tank down and pull the pump sending unit out of the tank without taking the fuel lines off the unit first. So yes they in fact had to take the lines apart.

Your answer statement above: A fuel line doesn't need to be disconnected to test pressure but it is under the hood. Their question is whether the fuel lines had to be disconnected to do a fuel pump change and the answer is yes and that was a side step answer or you did not read it all. Sure if there is no electrical issue at all a pump job can be done without pulling the negative battery cable off. I have done so myself but if so I disconnect it from the main harness first up by the bumper otherwise its a chance taken, are you to good to do so or just to cool to work or believe your just that good you know everything right, you know the future & got the big head. But that is not the point or the point for them being under the hood, they should of tested first always. To many shops & Tech's now days do not know how to test, they are parts changers, changing parts until they figure out the issue if ever. Its not yours is it, why bother not your money spent, and belittle everybody else you do not agree with? I am not belittled by you Before computer cars came along we learned how to test parts and electrical systems without a scan tool but I have one too it cost me about 20+ grand and its the old Snap-on brick 2nd one that came out bought new, used it though out the 1980's up to CAN1 came out and I have every key and Cartridge and all adaptors, manuals for every make and model ever made (bet you do not know what I am talking about), it cost way more then these new Snap-on's. Go ahead try to make people believe I do not know what I am talking.