Removing fuse/relay box 97-4.3 liter

June 24, 2005

97 c/k 1500 4.3 liter. I'm trying to remove the fuse/relay box to change a female connection for the fuel pump relay. I have the box off but I can't get the bottom cover off. I see where it reads lock release but I can't figure it out. Also the wiring diagram shows the fuel pump being fed from the relay and the oil pressure switch with the engine running and 40 psi of fuel pressure I pull the relay and the engine dies. I thought the fuel pump would pick-up power via the oil pressure switch.

GM-Tech · June 24, 2005

97 c/k 1500 4.3 liter. I'm trying to remove the fuse/relay box to change a female connection for the fuel pump relay. I have the box off but I can't get the bottom cover off.

This is not repairable. It's not just a simple terminal, as you will see if you do get the bottom cover off. You'll probably have to destroy the box to get it apart. If you do get it apart, you'll see the female terminals for the various fuses and relays are actually part of larger buss bars that sprout many terminals. Even if the one in question is all alone, it's still not just a terminal on a wire. There is no wire inside the box. Kinda hard to explain what it all looks like.

Assuming a 1997's UBEC is the same as newer models... Once you totally remove the connectors, you're left with a tube like component that is threaded on the top side of the box for the screws that hold the connectors on. These "tubes" also act as big rivets. If you look at the bottom side of them, you'll notice that the bottom of the tube is flared over. The square, threaded part on the top is the head of this "rivet" and the bottom, being flared, keeps the box together. You'll have to grind, drill or somehow remove that lip from the "tube". Even then, they don't want to come apart.

If none of these things on your box looks like this, wait until I take a peek at an older truck, if we have one in service.

June 26, 2005

Did you mean to say something?

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Yes thanks for saving me alot of work. I recently changed the fuel pump (aftermarket master) since then the pin-30 on the relay is melting the plastic. I replaced the original realy and the second one is melting in the same place. The female socket was also melted. Any ideas what could be causing this. Thanks again for the info on the fuse/relay box.

June 26, 2005

Did you mean to say something?

<{POST_SNAPBACK}>

Yes thanks for saving me alot of work. I recently changed the fuel pump (aftermarket master) since then the pin-30 on the relay is melting the plastic. I replaced the original realy and the second one is melting in the same place. The female socket was also melted. Any ideas what could be causing this. Thanks again for the info on the fuse/relay box. Also when I pull the relay with engine running and 40 psi of oil pressure the engine dies and I can't find the oil pressure switch. SFI model.

<{POST_SNAPBACK}>

GM-Tech · June 26, 2005

The female terminal in the fuse box probably has low tension, causing some resistance which results in heat being generated. That's what's causing it. I looked the last two days for a 97 or thereabouts, but we have had nothing in service like that. Had some 93's and 94's, but everything else has been 2001 and above.

Now, onto the problem of posting messages with no content. Can I help there? Is there some sort of problem with the forum?

June 25, 2005

97 c/k 1500 4.3 liter. I'm trying to remove the fuse/relay box to change a female connection for the fuel pump relay. I have the box off but I can't get the bottom cover off.

This is not repairable. It's not just a simple terminal, as you will see if you do get the bottom cover off. You'll probably have to destroy the box to get it apart. If you do get it apart, you'll see the female terminals for the various fuses and relays are actually part of larger buss bars that sprout many terminals. Even if the one in question is all alone, it's still not just a terminal on a wire. There is no wire inside the box. Kinda hard to explain what it all looks like.

Assuming a 1997's UBEC is the same as newer models... Once you totally remove the connectors, you're left with a tube like component that is threaded on the top side of the box for the screws that hold the connectors on. These "tubes" also act as big rivets. If you look at the bottom side of them, you'll notice that the bottom of the tube is flared over. The square, threaded part on the top is the head of this "rivet" and the bottom, being flared, keeps the box together. You'll have to grind, drill or somehow remove that lip from the "tube". Even then, they don't want to come apart.

If none of these things on your box looks like this, wait until I take a peek at an older truck, if we have one in service.

<{POST_SNAPBACK}>