I apologize in advance if this is long-winded, I'm trying to give as much detail as possible.

My wife's 2001 blazer has been having intermittent starting problems, in that occasionally it won't turn over at all, with SECURITY flashing. Normally she just keeps f'ing with the key trying it again and again, and it will eventually start.

I did some research and figured it was probably a bad ignition switch, so I bought a replacement switch and sat on it for a few weeks, until a couple days ago she got stranded and we had to leave it overnight in a parking lot. The next day it started right up and we brought it home, and today I replaced the switch using these instructions.

I went to do the 30 minute relearn, but it wasn't behaving as the instructions said it should. The security light would turn off after a few seconds in the ON position, but the engine still wouldn't turn over at all.

I decided I was fed up with passlock all together, and attempted the solder-in-resistor bypass method, but I wasn't getting any connectivity at all between the orange/black and either side of the cut yellow wire so of course no Ohm reading. After giving up for the day I realized maybe I should turn the key ALL the way to crank to get a reading? I had been trying it only in the ON postion.

Well I had read in one post that even if you can't find a resistor to match the ohm reading, that you can use any resistor from 500 ohms to 13k ohms, then just relearn. Now I'm guessing that advice was incorrect?

I had a few 4.7k resistors on hand so I soldered one in and re-attempted the relearn. This time I saw different behavior: Move the key to on, SECURITY light goes out after a few seconds, move key to crank, and SECURITY light flashes for 10 minutes, then goes out. "Yay", I says, this should work.

Well after 3 cycles of waiting 10 minutes, turning key to off, then on, then crank again... no love. Now the security light goes off after a few seconds again but still no crank. I then soldered another 4.7k in series, security light flashes for 10 minutes three times... but then security light goes off after a few seconds again and still no crank.

Having googled and read and searched forums and read until my eyes are wearing out, I'm getting frustrated.

I note that most people report the passlock cuts fuel to the injectors but engine will still turn over. This has never been my issue, it won't turn over at all.

I'm confident I installed the switch correctly, ACC works as it should, etc...

To make things even more confusing, once after I installed the new switch, before monkeying with the bypass plan, it started right up. I turned it off and then it just wouldn't start again.

ARRRGH! I'm pulling my hair out here, any and all advice appreciated short of "take it to a dealer". I don't have the cash and my feeling is that I'd get more satisfaction setting the damn thing on fire LOL J/K but ugh if that's what it takes...

Thanks

Edited to add: I don't know which version of passlock I have, but the keys have no resistors on them... just regular metal keys.

 

I'm now wondering if maybe passlock isn't the culprit at all... can passlock actually cut power to the starter?

What else could possibly cause the engine to not turn over like that?

I think it HAS to be related to the new ignition switch just because it always reverted to starting before, and today it randomly started once, then nothing for 8 hours of multiple tests and rests and double-checks, etc.

I don't hear anything when I turn the key to crank except a relay under the dashboard.

If it's relevent at all, I guess I should note that in the past this blazer has done other weird things related to wiring/electrical, such as maybe a year ago the headlights didn't come on though set to auto, then after moving the switch to "on" they flashed quickly on and off for a few seconds then the whole car's electrical went out for a few minutes. Also the factory horn alarm seems to rarely go off randomly (in a rural area), last time was a couple months ago.

Just thought if I had more detail, I should offer it... might be something obscure.

 

Well i can tell you that yes passlock can cut the power to your starter, I plugged a factory cd player in my truck from a junkyard 1 time that had passlock active , Once i turned my key on "Loc" came up on the radio, The truck would not even crank until i changed the radio back to my original, And disconnected the battery & reconnected it.

 

Bump.

The Blazer still hasn't moved, I've spent another day working on it.

Here's basically what happened:

I went back the next day, and it started on the first try. I said, OK, still fed up with the passlock system, cut the yellow wire while it's still running.

I did that, and it started a few times in a row, then quit starting again (no power to starter).

I tried again to get an Ohm reading and discovered that resistance was way high until I tried to start the car then it would consistently deliver 14.57k ohms even after I released the key to the ON position. I then soldered three 4.7k resistors in series and measured the total resistance at something like 14.51k. That sounded close enough and I soldered it in between the black/orange and the yellow going back to computer. Then I attempted the 30 minute relearn sequence with no love.

I spent the next few hours waiting ten minutes and turning the key off then on, then trying to start, etc....

I disconnected the battery for a few hours, then reconnected it and left the ignition off with no key overnight.

Next day it started the first few tries then, nothing.

I'm still wondering whether I have a passlock problem or something else. The SECURITY light is always either on or flashing now.

Is there anything else I can test before taking it to a dealer?

 

The passlock system does not inhibit the starter. You either have problems with the ignition switch not passing power properly to the starter. Wiring diagrams for the ignition switch can be found in the thread linked to in my signature. You can also test for power at the small terminal on the starter. If you are not getting power there, then you have to trace back through the system.