Hi All,

I have browsed thru the several threads dealing with security and passlock
issues, but have not found a remedy yet.

99 s-10 blazer been working fine, yesterday it would not start battery is
was weak, I had planned on replacing this wk, so I thought no big deal.
I jumped it to get it started so I could drive to town, it started then quit.
Noticed the security light on, so I figured new battery would solve it.

Got new battery installed, but still having problem with security. I can disconnect battery for 10-15 minutes, and then start it and it will run,
but security keeps flashing the light relays, dash lights flash,etc...

I have tried using key fob to disengage security, but it does nothing, also
tried several times to relearn passlock, but no success.
I noticed that during the relearn steps the security light and dash lights will
stop flashing for about 10 secs then resume, so figured that was the point to
turn key off for the 5 secs and then continue.

So am doing this correctly?

Anyone else experience this security issue after replacing battery?

It does not seem it should be this difficult, to just replace the battery
and have all these problems to boot.

Any advice would be appreciated.

Chris99

 

How long does the security light stay on before going off while you are doing the relearn?

Will the truck stay running if you wait 10 minutes with the key in the 'run' position before trying to start it?

 

Security will stay on for approx 7-9 minutes before going off.


Yes, truck will start and stay running.


Chris

 

More info...

I ran across a thread discussing GM relearn, and it adds the step of using a
scanner to erase codes before starting relearn steps.

I tried using an Equus 3130, but can not maintain a link long enough to do it.

When the key is set to Run, the BCM box is the unit doing the most beeping,etc... and I guess is interferring with establishing a scan link.

I am concerned about driving to GM dealer [30 miles] with BCM squaking
away, will the vehicle make the trip or will the security system shut it down?

Chris

 

If you turn the key to the 'run' position and wait 10 minutes before turning the key to the 'start' position to start the engine, the passlock system should not interfere during that key cycle.

It sounds like there is an intermittent contact inside the ignition switch causing things to go haywire on you. Have you tested the inputs/outputs from the ignition switch using the diagrams in the ignition switch link below (see sig)?

 

Ok,
I did a new test this morning.

1.disconnect battery for 10 min.

2. turn key to run position for 10 min.

3.try starting.

result, the truck started and no security light, no flashing head lights,etc..
I let it run for about 10 min, shut it off and restarted no security light.

Took it for a drive about 15 min, I had the heater on, fan blowing, then
security light came ON and A/c came on. wtf????????

I drove home, turned it off and restarted, but the security light is still ON.

Very frustrating........ I will try the above steps again and see what results
I get, and read thru your ign tech note.

Chris

 

Update on testing today.

No local parts shop has the ign switch in stock, so it would have to be ordered, so thought I do more of an examination, based on other comments
I have read that it can be done without full removal or having springs pop out.

I detached ign switch from steering column, carefully pulled off the covers and examined the contacts, they had some black deposits on each.
Cleaned them with CRC contact cleaner and put a tiny dab of dielectric grease on each. They cleaned up easily,they were not as bad looking as those pictured in the ign tuturial. I also cleaned the connections for the 2 other wired connections.
Put everything back together, reconnected battery, set the key to Run for 10 min, BCM immediately began squaking, I did notice the Security light went out after 4 min, tried starting after 10min but no success, it will crank and fire briefly and Security light came back on.

Battery needs a charge before more testing can occur.

So based on my examination of contacts, do you think that can still be cause
of Security issue?

Question, is passlock sensor part of the 3 wire assembly that connects to
lock cylinder? There is small heat shrinked bundle about mid-way on this
assembly. Anyway to test this sensor, aside from trying new ign switch?


Chris

 

Late afternoon, finally got bat charged and installed.

Set key to Run and waited 10 min, the Security light stayed ON and
BCM was squaking away, left it for another 5 min, still no change.

I tried starting anyway, and no success, it cranked, fired for a few secs
and died, Security light ON.

I was examining the wires around key/lock assembly and noticed that the
white plastic / metal module that has the manual button to release key
was too hot to touch, so detached and let cool.

What does this module do and should it get hot?

I disconnected bat and will try another reset test in a 10-15 min.

Chris

 

Update #3.
Left bat disconnected overnite.

Reconnected this AM, locked all doors with drivers pwr dr lock, closed the
door, used key to unlock both driver and passenger doors.
Opened drivers side, inserted key and set to run, no security light ON, no
squaking Bcm, let it sit for 10 min, about 4 min into the cycle, the BCM started
squaking and Security light came ON, I let it go the entire 10 min, and tried to
start, no success, it cranks, fires and dies.

So what to do? Advice would be appreciated !!!

1. replace switch? [exam/cleaning of switch was done and it did not show extreme scorching] so I am not certain it is culprit.

2. tow it to dealer and have it scanned, put into relearn mode?

3. other recommendations?

Chris

 

The BCM squawking away isn't a good sign, but you have not provided enough information to make any determination as to it's cause. You really need to get it to someone that can look at the data stream and figure out what is causing things to go screwy. You may have a problem with the BCM.