I have read the different posts on fuel pump diagnosis, but still confused I guess. I went to start my 98 blazer today and it would not start. It has plenty of juice, but it's acting like it did when the fuel pump went out 2 years ago. I can't hear the pump "hum" when engaging the ignition. I switched the relays in the under hood fuse panel, and no change.

The only problem I have been having with the blazer is an intermitent wiper problem. Seems like there may me a short or bad wiper motor. Sometimes they work, sometimes not. I do not know if it could be related. Any thoughts on this?

 

*Moving to 2nd Gen Tech*

One common theme with all fuel pump problem threads is the suggestion to test the fuel pressure. That should always be the start. Test the fuel pressure with the key on. It should read 52-60psi. Then turn the key off and watch the fuel pressure. It should not drop more than 2-3psi in the first 30 seconds or so. If it does drop, it should level off after a minute or so and definitely should not drop all the way to zero.

As far as your wiper motor is concerned, check out the DIY thread - Fix for cold solders in the Wiper Motor

 

My 98 also would not turn over, so I could not do a pressure test while it was running and there was no "hum" either when you turned the key to the on position. In the haynes manual I have, it says that there is a direct line to the fuel pump to help test it or jump it.I could not find it. So what I had to do is find the direct wire, gray wire,going back to the fuel pump coming out of the hood fuse block and stick a straight pin in the wire to check for voltage going back when the key was turned. I was notgetting voltage going back. I myself could not test at the tank because the was no room to get my hand up there without dropping the tank anyways. It did turn out to be my pump and changed it, no problems, in that area, since. of course my tank was the 19 gallon tank meaning bigger $.

 

I have noticed more than one poster trying to test the fuel pressure with the engine running. As Kyle said in his reply, youfirst test the pressure with the ignition key in the 'on' position, not with the engine running. This way, it's irrelevant whether or not the engine will run.