I have a 97 blazer which just started last week to quit starting.. when i turn the key i get lights on dash some hum from fuel pump - and that is all.. nothing more.

the first time it happen - i jammed it hard into park - and it started for me - but wouldnt again -- until about a week later.. during the week i tried about 30 times.. and nothing - but i figured i would try again - after sitting a week and it cranked - ran it for about 40 minutes ,shut it down and nothing again..

I replaced the starter.. it was dragging some recently,.. so i figured if not now it would need soon.. anyhow it didnt fix the problem - so i replaced the neutral safety switch -- the original connectors were glued in - but i dont think they were damaged taking them out - i was careful to not pull wires free. anyhow - that too was a no go.. i have had the ignition switch replaced two times - last time was about 1 year ago maybe a bit more.. - anyhow i dont know where to go now - or the best way to go about testing for shorts etc.. fuses etc.. pls help

 

Have you checked the connections at the battery to make sure they are clean and tight?

 

battery fully charged and tested - contacts good, they were removed twice and reconnected for the replacement items i mentioned, - verified starter cranks.. - but smoethign wrong between ignition switch and starter. - really thought it was the safety switch.. - i cant imagine its the ignition switch as this was not typical symptoms i experienced with the ignition switch.. how i can i test to see if things are bad before or after the neutral switch. --- to see if the problem is before this or after.????? anywhere to trace this?? inline fuses?/ i have checked the fuse box - all look good there.. - i heard some saying that maf sensor can cause this ?? can it be.. ?

 

I have not really heard about the MAF sensor causing this.
I have on the other hand heard about the ignition switch causing problems like this.
Multiple times actually with friends vehicles and my father in laws car, ignition switch was bad, car sometimes would fire right up.. but other times it would not do anything, all interior lights would come on, everything, but you turn the key to start, and not a thing.
as for testing it, I am not too sure.

 

ok this is really weird - well today it started .. again ..

but - its warm out - and it didnt start when it was much colder - so its definitely not a temperature thing..

It was sitting 3 days - just like last time - wont start no matter what you do - but let it sit 3 days or more and cranks right up.. wtf... this doesnt sound like a short - or a switch that is randomly working.. it sounds like somethign that might have some sort of stored charge.. maybe an ignition coil or something/?/ is there some resistor or capacitor other than the ignition coil that can do something like this starting problem?

 

Check the starter relay in the underhood fuse box, swap it with the headlamp relay and see if the problem goes away, if not then it very well may be the ignition switch but there are many possibilities.

 

i didnt find any underhood fuse box.. where is that located - only relays i saw are the three bosch relays on the firewall . i interchanged those already.. no difference..

anyhow - so strange the car can sit 3 days or more and start. and i can try it 100 times right after shutting it down and nothing. and again it its not temp dependent - i can try it tomorrow in the am and nothing.. but i am pretty sure 3 days from doing notihng - i will be able to go out there and start it on first try.......

 

My bad, i guess there wasnt an underhood fuse box in 97, that started in 98. You need to find a fuse labeled "Crank" Fuse panel inside drivers side door jamb on end of dash, bottom row second one from front of vehicle. You need to connect a test light to a good ground and test to make sure your light is working, probe the crank fuse while turning the key to start, if it lights, the ignition switch is ok, if not switch may be bad. This is a start to solving your issue, post back your findings

 

thanks - i will give it a test and post back

 

good ground bracket - just above hood release.. but the crank circuit shows no juice.... pls tell me not ignition switch.


is possible that if something is wrong with voltage regulation this can not crank????? maybe something internal in the alternator.....