Security Light

biochemist · March 31, 2005

Hey GM-tech...this morning I took my daughter to daycare, left the truck running and came out a couple minutes later...the security light was on. I turned the truck off, back on...it was off then...drove to work, played around a bit...again, came on. I should note the alarm works as stated in the manual and the truck never ran any different...always started fine etc...even with the remote starter. The dealers around here assured me the RS is the cause...sure enough I took it to the installer and he tested the resistance of the module using a multimeter (I guess resistance is what "runs" the Passlock system from what I have been told) with the truck running, as soon has he touched the module with the electrodes the light came on (nice to see reproduction of an issue I might add )...he said the resistance was a bit low and it set the light, adjusted the dip-switches on the passlock bypass module, measured again, not a problem now! (he said the original installer should have set them this way and it was just on the "edge" of being in spec and with the warmer weather we have it must have changed the resistance...note the starter was installed in november...Now, I called my dealer and they said (other than we told you so ) that that is common (installer said this also) and that the system is fine now...the light has not came on again...so my question is although the manual is not specific except stating that if the light comes on while driving your fuel bypass is not working and to get serviced, is the system OK, in other words, if someone steals my truck now will the gas cut out on them as designed? They told me as long as the light shuts off, the system is functioning correclty...just want to make sure. I would assume if there was an issue the light would be on constantly even after restart and the truck would stall due to fuel cutoff? Is there a test for this other than trying to steal a truck.... ... Thanks, later,

GM-Tech · March 31, 2005

If the security light stays off, your system is working.

biochemist · April 1, 2005

If the security light stays off, your system is working.

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Thanks for the quick reply, that is what I thought...am I understanding on how the system works...resistance? It is just that the manual is unclear, I mean 60 pages on seat belts and kid seats, but 2 paragraphs on the security (I am all for saftey but...wow)...I guess you have heard of this type of thing before with remote starters? Does it reset everytime you cycle on and off? Anyway, I guess if it does not come on all is fine and if it does come on while driving a cycle will reset, and if something is really not right the light will stay on all the time?, thanks again, later,

mcreyaufmiller · April 1, 2005

In October/November I had a similar problem with my 98. It turned out to be the Remote starter/bypass unit in my truck. The only way to fix it was to remove the system and replace the wiring harness. After spending over $500 not to mention what I had invested in the now trash remote starter, my truck is back to normal and I have no more problems. After a lot of research, I found that the viper system is the only one that will not screw your electrical system on the Chevy's.

GM-Tech · April 1, 2005

Thanks for the quick reply, that is what I thought...am I understanding on how the system works...resistance? It is just that the manual is unclear, I mean 60 pages on seat belts and kid seats, but 2 paragraphs on the security (I am all for saftey but...wow)...I guess you have heard of this type of thing before with remote starters? Does it reset everytime you cycle on and off? Anyway, I guess if it does not come on all is fine and if it does come on while driving a cycle will reset, and if something is really not right the light will stay on all the time?, thanks again, later,

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The BCM learns a certain voltage value to determine whether or not to allow the vehicle to start. So yeah, ultimately, I guess the remote start systems use some resistance value to drop the 5 volts down to a valid value and allow the vehicle to start. I know nothing about aftermarket remote start systems so I can only guess how they do it.

biochemist · April 2, 2005

In October/November I had a similar problem with my 98. It turned out to be the Remote starter/bypass unit in my truck. The only way to fix it was to remove the system and replace the wiring harness. After spending over $500 not to mention what I had invested in the now trash remote starter, my truck is back to normal and I have no more problems. After a lot of research, I found that the viper system is the only one that will not screw your electrical system on the Chevy's.

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Well, my Astrostart has been great, it is the bypass module that had to be adjusted I think. The original tech who installed it did not set it just so and with the temp warming up it finally got low enough to trigger the light, or this is what the installer tells me, he said it measured just a bit too low and triggered the light. I looked at the sheet, there are hundredes of settings, he says the original guy was two steps too low (or two high I cannot remember)...he set it right this time... All I know is that the truck was running and he tested the resistance with a multimeter, and as soon has he touched the electrodes to the connections the light popped on...so that is when he looked up the proper value and set it with the dip-swithces...no light when tested and no light since...I think you just have to have an experienced person install you system, it is not trivial....I researched before I bought and Astrostart was highly recommended...it has worked flawlessly I might add...it was the bypass that had to be adjusted...Thanks for the info GM-Tech BTW...hope this helps, later,