Feel like trying to diagnose a S10 issue? - F-Body Road Racing and Autocross Forums

It's a Gen 1 94 S10 Blazer 4 door 4x4 with the analogue dash and the 4.3 Vortec/ A4. It's sitting in a parking lot currently.

Drove the truck around all day (city driving), very rainy, no problems at all, acted normal. Towards the end of the night I went to get back in and start it, and this is what happened.
Unlocked it with the remote,
interior lights turned on when I got in,
put the key in and the dash lit up,
turned the key to start and every light in the truck died.
Turned the key again and nothing happens.
Pull the key out and then the rearview mirror light shines very dimly,
I figure maybe it's a dead/dying battery.
I open the door to get out and then the overhead console light turns on like nothing is wrong,
not a dead battery apparently.
Shut the door and the lights immediately go very dim and then fade to off.
Put the key in the ignition and turn to on and the dash lights up like normal.
Turn the key to start and every light goes out like the battery is suddenly dead
Leave the key in the on position and the dash slowly lights up to normal,
I try the overhead console lights and they work like normal
Turn the key to on and everything goes black.
I did variations on this several times, it always resulted in dim lights that would randomly light up like nothing was wrong even if I just sat there for a bit and didn't touch anything. Everytime the key went to start everything went completely black, like you unhooked the battery.

I'm guessing it's the battery cables going to the starter and alt. I'm going to test the battery before I buy new cables though just to be 100% sure it's fine. I've never seen anything like this though so any suggestions for other things I can look at would be appreciated.
Thanks for reading this through.

v7guy View Member Profile	Jun 25 2006, 12:37 PM Post #1
Advanced Member Group: Advanced Members Posts: 854 Joined: 26-December 03 From: NYC, NY Member No.: 50	It's a Gen 1 94 S10 Blazer 4 door 4x4 with the analogue dash and the 4.3 Vortec/ A4. It's sitting in a parking lot currently. Drove the truck around all day (city driving), very rainy, no problems at all, acted normal. Towards the end of the night I went to get back in and start it, and this is what happened. Unlocked it with the remote, interior lights turned on when I got in, put the key in and the dash lit up, turned the key to start and every light in the truck died. Turned the key again and nothing happens. Pull the key out and then the rearview mirror light shines very dimly, I figure maybe it's a dead/dying battery. I open the door to get out and then the overhead console light turns on like nothing is wrong, not a dead battery apparently. Shut the door and the lights immediately go very dim and then fade to off. Put the key in the ignition and turn to on and the dash lights up like normal. Turn the key to start and every light goes out like the battery is suddenly dead Leave the key in the on position and the dash slowly lights up to normal, I try the overhead console lights and they work like normal Turn the key to on and everything goes black. I did variations on this several times, it always resulted in dim lights that would randomly light up like nothing was wrong even if I just sat there for a bit and didn't touch anything. Everytime the key went to start everything went completely black, like you unhooked the battery. I'm guessing it's the battery cables going to the starter and alt. I'm going to test the battery before I buy new cables though just to be 100% sure it's fine. I've never seen anything like this though so any suggestions for other things I can look at would be appreciated. Thanks for reading this through.

firehawkclone View Member Profile	Jun 25 2006, 01:58 PM Post #2
Grumpy Group: Advanced Members Posts: 2,722 Joined: 1-January 04 From: Bakersfield CA Member No.: 81	It could be your Batt so just jump start it and see. If it is than have your ALT checked. Than check the cables, starter, Ign switch..... It's a P.I.T.A

John_D. View Member Profile	Jun 25 2006, 03:42 PM Post #3
Engine and Tools Moderator Group: Advanced Members Posts: 1,859 Joined: 23-December 03 From: Lebanon TN Member No.: 6	A nearly dead battery can light up the interior lights and dash, but when you hit the starter, it takes the battery on down to nothing. After a bit, the battery will come back enough to light those things up again. Try the headlights and see if that knocks everything down too. If so, then it's the battery/alternator/connections. How old is the battery?