security light sometimes won't start. Why?

[95 3800 bonneville]

I got a 1995 Pontiac Bonneville witrh 84000 miles in mint condition for $4000 recently. It's the nicest car I've ever owned. I test drove it hearing a glinding or left front wheel bearing lack-of-grease-type noise. The used car dealer promised to take a look at it, but it's hard because I work every day and need a car to get to and from work. This problem seems easy to solve, a look, and maybe some grease is needed. However, a few weeks after I drove it, this "security" light occasionally comes on. It sometimes stays on after the car is shut off. Other times, it won't start. Sometimes it will come on go off, and restarting is no problem then. When it came on, I opened the hood, and shut the hood, and the car allways (so far) has re-started when I tried. Also, my key is one of trhose with a chip in it. Could the security light problem be a result of a bad key chip? The car drives, stops, manuvers, and performs at about 20MPG on gas and all fluids, braking, trans, shocks, radio, power everything seem to work very well for an 11 year old car. Do I need a new key made to solve the security light problem? This car does not have any alarm system that I'm aware of.

[GTRider0]

i had a 93 and the same thing happened to me and i prolonged it untill i was sitting in a parking lot and i couldnt' start my car and i had it towed to a pontiac dealer and they told me that it was the ignition switch was bad becuase it wouldn't relay the signal from the key to the rest of the car

so if you dont want to be sitting a parking lot somewhere i would suggest doing this it cost me about 256 dollars i do believe labor and all

[richtazz]

THe ignintion cylinder reads the resistance of the chip to verify the correct key is inserted before allowing the car to start. If you (or your significant other) has a huge wad-o-keys/trinkets, stuffted animals, etc.... hanging from the ignition, you'll need a new ignition switch. It's possible the key is just dirty. If you look at the key, there is a black chip with a metal strip across the middle. Clean any oil, gunk, pocket lint from this metal strip (it's the resistor) to be sure the ignintion is getting a clean contact. If cleaning the key doesn't work, it could be the wires leading to the ignition switch for the security (part of the iginiton cylinder assy) are broken, common problem.

[jjm01o]

Where is the ignition switch located? I had the same problem with my 93 8 years ago, and the same problem is occurring again. I believe it us just under the dash near the steering column, please confirm. The symptoms I have are when I go to start the car, it just clicks, and nothing. I then wait the recommended 10 seconds between start attempts to save the battery. After about a couple minutes it will eventually start. It's annoying as hell.

[richtazz]

The ignition switch is mounted in the steering column. The wires I was referring to are part of the ignition cylinder assembly. They are very thin and become brittle with age, or will break internally due to metal fatigue if you adjust your tilt wheel often.

[GTS767]

I have a 95 Bon SSE, and experinecing similar prolems. I read the post and tried to find how to remove the ignition switch. I assume it should be the piece in the control column where the key fits into. But can you PLS advise how to remove it. Do I have to remove parts of the control column. I was unable to see any screws or other for disassembly. Any insight on how to remove is appreciated.

[Mickey#1]

A problem with Vats (vehicle anti theft system) will usually mean the security light is staying on & the starter is disabled. If this is the problem with your car here are a couple things you can try.

Another key - the contacts on the key can wear down & no longer make a good connection with the contacts in the lock cylinder.

Clean the contacts - use an eraser on the key. I've heard you can clean the contacts in the lock with a cotton swab & alcohol.

If you're still having trouble you need to check the resistance of the key pellet. Once you know the resistance you can check the wiring under the dash. There are two wires in a plastic sleeve that come from the steering column to the dashboard. Disconnect these wires and connect the meter to the wires that go up the steering column. Insert the key & check the resistance while turning the key. The resistance should be very close to the reading you got from the key & the resistance shouldn't vary while turning the key to the run & start positions. If you're getting a bad resistance reading you'll have to bypass reading the key or replace the lock cylinder.

Bypass - Purchase resistors having the same resistance as the key & wire them into the wires coming from the dash. Shouldn't cost more than a couple dollars if you do it yourself. Any shop that installs remote starters can also do this for you.

Replace - I've never done this but think this is how it works. The new lock cylinder will come with a key that doesn't have the resistor pellet. Before installing you'll have to get a key cut to match the new key with a blank that matches the resistance of the old key. This will cost a lot more than the bypass.

[GTS767]

Mickey, thank you for the wealth of information. I will check as explained.

In my case, the car will start but the security lite will remain On and will extinguish after a minute or so. Two nights ago, though, the whole neigborhood woke up to the sound of the alarm on my car. It was tough. At this point I pulled the connectors from both horns on the car and I keep it unlocked during nights. I also cleaned the key resistor with an eraser. Also I pulled the fuse to the alarm and cleaned it as well. I even tried a different key that I have but still no change.

I will check per above procedure and let you know.
Thanks

[MT-2500]

Originally Posted by 95 3800 bonneville

I got a 1995 Pontiac Bonneville witrh 84000 miles in mint condition for $4000 recently. It's the nicest car I've ever owned. I test drove it hearing a glinding or left front wheel bearing lack-of-grease-type noise. The used car dealer promised to take a look at it, but it's hard because I work every day and need a car to get to and from work. This problem seems easy to solve, a look, and maybe some grease is needed. However, a few weeks after I drove it, this "security" light occasionally comes on. It sometimes stays on after the car is shut off. Other times, it won't start. Sometimes it will come on go off, and restarting is no problem then. When it came on, I opened the hood, and shut the hood, and the car allways (so far) has re-started when I tried. Also, my key is one of trhose with a chip in it. Could the security light problem be a result of a bad key chip? The car drives, stops, manuvers, and performs at about 20MPG on gas and all fluids, braking, trans, shocks, radio, power everything seem to work very well for an 11 year old car. Do I need a new key made to solve the security light problem? This car does not have any alarm system that I'm aware of.

Welcome to AF on your first post.
A good engine capable scanner should show a code on it and point you to the problem.
If you can get code post back code no.
MT

[Mickey#1]

There should be switches for the trunk & hood, check both of those out. The trunk switch has been known to cause problems.