Intermittent loss of electrical when trying to start

[bgooserow]

My 89 S10 was working fine when I went out mid-day to go somewhere and as I turned the key the dash lights flickered and I lost ALL electrical. No door light, radio, clock...nothing.

Opened the hood, poked around, checked battery connections, etc. and suddenly the under-the-hood light came on. Got in cab, shut door and all electrical disappeared again. Got back under the hood, poked around some more and as I moved a set of wires next to windshield wiper motor...the hood light came back on. Got in and everything started fine! Only problem was that the clock was now wrong.

Everything functioned normally for one day, then I got in to go somewhere and the identical thing happened. This time, no moving of wires, tapping or checking of fuses, etc. had any effect. I sat in the truck wondering what to do next and the interior light came back on and I was able to start up and go...again, just the clock was no longer on the right time.

Again, everything was fine for 2 days...multiple times starting and re-starting the truck with no problems. Then Saturday, drove to another city; parked for 5 hours and then went to leave and NOTHING! No electrical at all...not even the interior light.

Played the same game, touching, moving, testing, checking anything I thought might be involved...connections to battery, fuse block, wiring bundles, alternator, anything....and finally...when I wasn't touching or moving anything (just standing there disgusted) the under-hood light came on. I quickly went to the cab, twisted the key and briefly saw a red light or two come on (normal stuff) and then NOTHING AGAIN. So, I waited 10 minutes, just watching and the hood light comes back on, I get in and start it...and it works! I drive it for another hour (freeway). Run several errands (stopping, motor off, starting, etc.) and no problems. Next day...no problems...even a 3-hour trip home.

So, I'm really lost on how to even begin to track down even the beginnings of this one. The ONLY thing that MIGHT be common among each of these occurrences is that it seemed to happen during the hottest part of the day (and in Las Vegas that means around 100 this time of the year). But why now and not last month during the 108 degree days?

Is there anything such as a 'thermal cut-off' that shuts down the electrical system when it's very hot?

Any help would be appreciated.

[DoCTa09]

Wow..i am kinda relieved to hear this...what you describe is the exact same thing my truck is doing to me...and it happend when it was sitting in the hot sun for and extanded period of time...lots of batter power but not power anywhere...puzzleing really!! I hope that someone has a n answer for us...Cause I am sooo lost with this one. Shaun

[DoCTa09]

ok ..im my case here I think I can rule out the heat scenerio...I just went down to start her up and it did it again...one click from the relay to the starter and then dead...3 seconds later a ding ding ding and the power is back. Tried it again and the darn thing started but would barely idle then stalled out. After the power coming back once again the thing starts up and is like nothing is wrong...PLease if anyone knows where to begin with this I would love to hear from you asap!! Shaun