2000 express turns off only in warm weather new fuel pump changed fuel relay it does get hot is this normal for fuel relay?

Answer 1

A relay should not get much hotter than the air around it. I clean carpet with my 1998 Chevy Express van and I noticed the same issue of the relay getting extra hot. This was because my van is stationary and the carpet cleaning machine runs from a drive axle going to the van's engine. Not only is there a rather air tight cover over the fuse compartment under the hood, but the engines heat circulating around this area doesn't help much.
Even with the issue of engine heat and a somewhat air tight fuse compartment, there shouldn't be excessive heating of the relay. Here are two reasons for the excess heat. First, if the fuel pump is demanding more current flow from the battery it can cause the relay to get hot. More resistance in the pump due to a poor connection, or possibly there is a physical resistance associated with the pump- a worn or seized bearing, a clogged filter etc. These are reasons a relay could get hot. Secondly, any poor connection- the wiring harness under the vehicle which is going to the pump has a connector that is notorious for heating and cooling/expanding and contracting, which will drive a person nuts. It took me weeks to figure out that this was the reason my van died randomly. I had gone so far as to remove the fuel pump and put a jumper between pins 87 and 30. At least if you do this you will be able to hear the fuel pump running, or not, without the noise of the vehicles engine drowning it out. It was at this point that I realized that this poor connection at the wiring harness was causing the increased resistance at the relay, and hence it getting hotter.
While we're on the subject of fuel pump relays, note too that it is the vehicles main computer that turns on this relay. If you've ever accidentally shorted out the computer's + to this relay to ground, you're fuse to the ecm ( electronic control module [computer]) might or might not blow. Either way there is a good chance that the computer will stop sending this 'switching' voltage to the relay. The computer is in charge of this relay primarily for safety reasons. In case of an accident the relay removes power to the fuel pump. A good thing this is surely, but buying a whole new computer in the event of this circuit failing can be cost prohibitive to many of us poor drivers. BTW, used computers at a pick and pull junk yard are pennies on the dollar compared to the dealership. I paid a whopping $27 for my 1998 Chevy express computer. The junk yard will give you a list of compatible models that have the same computer in them. I got mine out of a 2500 truck. No tools needed to do the job, but always unhook the battery before removal of a computer. These Chevy's have a tendency to die at stop lights after a computer swap, until it 'relearns' the idle setting. This is normal.
If you are short on cash, or in a jam and need to get your vehicle home, either bypass the relay with a jumper, or in the case of the computer not activating the relay to the fuel pump, you can simply run a 12+ wire to terminal 30 ( or whichever wire is + to the pump). If you take a wire from another 12volt+ circuit which is switched with the key AND remains ON during RUN ( like the 12+ coil[ be careful not to short out the ignition module]) then when you turn off the key the pump will also turn off.
For safety reasons always use a test light to find the proper wire, find a good accurate wiring diagram, and replace the computer as soon as possible.