Hi all, Been a while since ive posted. Havent needed much help i guess. Ive got an 03 s10 4x4 extended cab, 4.3 automatic. Thought i was trading up from my 97 blazer, i think i made a mistake sometimes lol. Its been having a no cranking issue. Ill turn key on, i get all lights and everything but no crank. When key is turned all the way the light go out as usual but come right back on then i let the key rest. Then a while later itwill start like theres no problems at all. Im also having issues with the battery light blinking on and off and voltage drop. This happens and then the light stays off and volts go back up. JUst wondering if there could be any connection between these two issuesor any ideas on where to start. Any ideas are much appreciated and i apologize if i missed a thread that detailed same issues.

 

ok so today the truck fired up no problem at first. It was also reading good voltage and no battery light. I went to the store and came out to a truck that wouldnt crank. after i flicked the switch quickly a few times it started up. Unfortunately it also had battery light flashing and low voltage. The voltage at back of alternator or stud was at around 11.5volts. I got in and barely made it home. The voltswere down around 9ish and the lights were very dim. I shut it down and tried to restart it. It cranked but didnt have enough power and just did the rapid click noise like a dead battery should. I let it sit for a while because i had other things going on. It sat for about 12 hours before i got to it. I just went out to jump it and figured id try it before hooking up the cables and it started up like new. Im truly baffled and any help would be greatly appreciated.

 

Typical intermittently internally shorted battery IMHO. They usually happen in cold weather and can really make you scratch your head. You're not the first and certainly not the last. Bad batteries can also cause alternators to fail, but the alternator is not causing your no-start (if after sitting it starts fine). Just know the alternator might also be damaged by trying to charge a shorted battery.

I would replace the battery if it is over 3 years old - just lump it and buy a mid-priced one at Walmart.
I would replace the battery if it is newer (most are still under full warranty and if you take it in completely dead (run it down by leaving headlights on) it will almost certainly fail the quick testing typically done without fully charging and you get a new one).
Either way, I would replace the battery and watch alternator function from there.
You can throw a know good battery in there as a test, if you have access to one.

Good luck

 

I just wanted to update... my truck is still on occasion deciding not to crank. I noticed that my auto lights had stopped working and that my driver side hid wasnt working when it did start and when it wouldnt start the hid was lit. I unplugged it and it fired right up. ive since put in regular bulbs and got the auto headlight working. It still on occasion maybe 3 times a week wont crank over. usually i just turn the key back and forth and itll crank. Im leaning more toward igniton switch but would like a confirmation if im on the right track. any help would be much appreciated

 

i wold also like to add that the alternator was bad and i replaced it as well