ac, fuel pump connection??

I was trying to figure out why the ac on my 99 4.3L 4wd blazer wasn't working. had engine running, was fiddling with the electrical plug going into the accumulator,(I had unpluged it and put a jumper wire into the female end to keep the compressor going)started the engine it ran a few minutes then died.It didn't want to restart(Cranked but thats it)after a few minutes it did restart but soon died now it wont start at all.there is no sound coming from the fuel pump when I turn key on.did my pump die or did I mess something else up?? Dave

When you jumpered the A/C low pressure sensor, you probably shorted out a fuse. Check the fuel pump/inj fuse and ECM fuses. Actually check all fuses too. You shouldn't have left an unfused jumper in that connector if put one in there at all. If A/C wouldn't keep running without the jumper then you might have refrigerant undercharge or a bad low presure switch.

I did check the fuel pump fuse (the black square one under the hood) I will check the ecm fuse. BTW the origional problem with the ac is that the compressor does not engage when I turn the ac on. Thanks for your reply Dave

Did you check the fuel pump fuse or the just the relay? Anyway check any fuses related to fuel pump/FI and PCM. I think your low pressure switch that you were jumpering is 5V PCM voltage, I'm not totally sure since I'm not looking at the wiring diagram for a Blazer. A short wouldn't normally hurt the PCM because the drivers will circuit break. Maybe if you unhooked the PCM fuse for about a min it would reset? But look for a blown fuse just in case. It's always possible your fuel pump or something decide to give out while you were jumpering the A/C in a strange coincidence :icon16:.

It must have been the relay.I will check things more thorough this weekend, when the weather is better..Thanks again for your help.it is greatly appreciated. Dave :smile:

all fuses are good.I was hoping I didn't have to change pumps expecially since I have a full tank of gas. but the last couple of days it was getting hard to start so I figured it was going out but was holding out hope it was something easy..Oh well I have changed it before with a full tank on my 2000 blazer,at least my fuel guage will now work! thanks again for the input..Dave

Did you try jumpering the fuel pump where the relay goes? I'd at least try that and make sure the pump doesn't work when jumpered before taking it out.

no I haven't tried that.how do you suggest I atempt to jumper the pump.

Take the fuel pump relay out and jumper it with a wire in the terminals.

sorry I didn't finish this thread earlier..It was my fuel pump after all. blazer is running fine.as far as my ac not working, I did not try jumping the compressor again. I charged it until the compressor started working on its own.off and on quickly at first.the more I charged the longer it would run. after a can and a half of refigerant it works! (I am in the lower blue half of the guage) thanks dave