I went out to start my Blazer (2000 4.3 4WD 140,000 miles) and it didn't start. Had to have it towed to the shop. The mechanic put in a new passlock module and still the same problem. Engine turns over but will not start, only sometimes. When it does run the Security light flashes. He figured out 2 things: #1 if he turns the key very slowly it will start, if you turn the key at a normal speed it won't start. #2 If the Blazer is out in the cold (there's snow on the ground) it won't start but if it is in the shop and warmed up it will start. So he ordered a new key cylinder and still have the same problem. All of the electrical tests on the computer check out OK but it acts like it's an electrical problem. Compression is good. Etc. It has a new fuel filter and the fuel pump was replaced a couple years ago. The battery has full charge and checks out OK while cranking. All fuses are OK. The mechanic has had my vehicle for 1-1/2 weeks and is baffled. Help - I want my Blazer back.
p.s. - I don't want to bypass the security.

 

You did not mention if the fuel pressure was checked. I would guess it was from what you wrote.

I have heard of the ignition switch going back in these. When you mentioned changing out the ignition lock cylinder, was that separate from the switch?

 

They rekeyed the lock so I guess that would be the switch. Thanks

 

I'm not so certain that re-keying an ignition switch changes out the electrical part where the problem could be.

I found this on RockAuto listed as the ignition switch:

https://www.rockauto.com/en/moreinfo...361461&jsn=488

Which is different from the lock cylinder which is listed separately.

https://www.rockauto.com/en/moreinfo...361461&jsn=518

 

By the way, I do have experience with an ignition switch going out; just not on my Blazer. It was on my 82 Honda Prelude. It happened while driving. The engine just quit on me. Fortunately it happened in a small town that was surrounded by many miles of open wheat fields. I had no cell coverage so I was able to use the phone of a local shop to call a friend. Turned out the electrical part had worn out with no warning. I found a replacement but the lock cylinder was integral with it although I was able to have it re-keyed.

For the Blazer, the lock cylinder and the switch seem to be not-integrated.

 

I did not see the part he called a cylinder. I will check on Monday. I'll keep you posted. Thank you

 

 

Replaced the lock cylinder and ignition switch and now starts w/o problem. Thank you Christine_208, next time I'll have the mechanic call you.

 

You are very welcome. I like it when people can benefit from the lessons I learned "the hard way!" LOL

 

Oh and Thank You for reporting back what worked! It is the follow-up posts that can be the most helpful for those who in the future have similar problems. I know I've been one who has benefited.