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Cadillac Repair/1985 cadillac eldorado touring edition


QUESTION: The security light stays on when car is off.  Can I disconnect its bulb to stop battery from draining

ANSWER: Hello,

Unfortunately, you do have a problem here. The factory alarms were an option, didn't do anything but cause problems for the owner and to make things worse, it is 29 year old technology.
I have over the years been saddled with trying to fix this junk (factory alarms) since their inception, right around 1985. In fact, when dealers could not repair these under warranty, they sent these problems to my shop.

Here s the problem with removing the security bulb from what I remember. The alarm is integrated into different functions of the vehicle. If you create an open (no bulb) other functions of the vehicle may not work such as the head lights, horn, etc.
Even currently, the absolutely worst thing that can be installed on a vehicle is a factory alarm. Commonly it is assumed that there is no one that knows better than how to protect the vehicle is a factory engineer. Yeah, right! I defeated the Ford transponder system with one wire! According to the Ford engineer and advertising information the PATS made the vehicle "virtually unstealable."
The system in your car is actually 1982 technology because from the drawing board to the tie the car is sold it takes about three years. In essence, the system was already easily compromised because being sold as new, it was already obsolete.
These old alarms were interesting because one could break the glass and the alarm would not trigger. In the case of your very nice car (I have owned probably about 8 of them)one could break tat big door glass and climb in, never triggering the alarm.
The steering column was very susceptible to defeat by breaking the left side of the column with a screw driver to get to the locking mechanisms. As little as 30 seconds a teenager could be driving the vehicle doing no damage to the ignition lock and without a key. (Our shop that did exclusively theft repair rebuilt over 10,000 of these GM Saginaw steering columns!)
Once the engine was started, the alarm would then trigger and the vehicle would be going down the road with the horn blaring and the headlights flashing. Real secure huh? The system was notorious f running down the battery until it was dead as well!

The first thing I would do is try resetting the alarm. Lock the doors with the inner door button and unlock by inserting the key into the driver's door lock and unlocking. That is the reset procedure.

Next try going on Ebay or Craigs and obtain a factory service manual. If you are keeping the car an invaluable tool you should not be without! There are diagnostic flow charts you can follow that will assist you in finding the problem. Then if you need parts, you will either need to go to a junk yard or search the web.
It could be that it is a minor problem to repair. A lose ground under the dash (there are many because except for the steel reinforcement, the dash is all plastic!
Over the years I have had many requests asking if the security light bulb could be removed to bypass this factory installed junk. My answer has always been the same because I have for the past 30 years tried to successfully bypass these factory alarms, and the factory already thought of that from a security point of view, creating more problems because of integrating major circuits in the vehicle with the alarm.
I am not telling you that you can't try it, but you may be opening up Pandora's box.
Personally though, I would attempt to repair the problem in the first place instead of tring to throw a bandaid over the problem only to cause diagnoses problems the next time there is a problem with security.
As I said, I owned many of these and most were Biriatz's and I absolutely loved them. One needs to know the inherent problems though. The factory alarm. The heater blower speed resistor module that when it fails, it will run the battery flat! Can't buy replacement pars requiring a toggle switch giving you high blower and nothing.
Another problem is the trunk pull down and instead of replacing the motor, its best just to just adjust the slots in the latch and close like a normal trunk. The rear suspension was a problem either because of leaking air shocks, lines or the compressor. The HT 4100 engine was either good or bad and most came with the notorious wrist pin knock in the pistons. Didn't hurt anything,just an annoyance. The engine is all aluminum and cannot be overheated even a little bit! The hot light comes on shut the engine off right there, no matter where you are at! Even though it is common for thermostats to be changed in this instance, the thermostat was never the problem! Power antennas were a problem in which the cable would break. A motor is not needed, but merely a mast kit.
As I stated before, the columns are very vulnerable to defeat. I would suggest that if you are keeping the vehicle, have an after market paging alarm installed. No one is concerned about alarms going off and you are notified if someone is attempting to break in the car.

It may sound like I am making your car sound problematic. Like any vehicle, they had inherent problems and although you asked me about the security in the vehicle, since I am so familiar with these vehicles, figured I would give you a heads up to the very common problems with this type of vehicle. Not a big deal, just things to watch for.
If any of these issues come up for you, I can guide you through them.
Good luck!

---------- FOLLOW-UP ----------

QUESTION: Can you send me a list of the most common causes for this problem so I can troubleshoot or do you know if the owners manual I got coming will have that info

Hi Donald,

The owner's manual will only tell you basics about the vehicle and may tell you as to how to reset the alarm as I did. There is nothing in it about diagnoses to your problem. This is why I suggested obtaining a Cadillac Eldorado/Seville factory service manual for this problem and anything else you may run across.
I can give you an idea as to what I have run across, but the problem in that situation is that you are chasing ghosts and lots of labor, possibly to find that wasn't the problem.
One such example would be a broken or loose wire inside the driver's door. The door trim panel needs to be removed which is no easy process working with old brittle plastic with hidden screws I don't even remember a to where they are located anymore. Please keep in mind I worked on these and many different makes and models having to replace broken door glasses as well as fixing factory alarms. The manual's flow chart would help you confirm or deny this being a problem and possibly take you somewhere else.
As stated before, under dash grounds were a common problem for a variety of complaints. Over time the ground bolt can shake loose enough that there is a problem with the ground. The manual identifies as to where all these ground points are.
It wasn't very common to find a defective alarm module located under the dash, but it could happen. Again, the service manual with the diagnostic flow charts helps you eliminate that as being the problem or directs you if it is.
The system is tied into the headlights as well as the horn and there could be an issue in that direction.
As stated, the most common problem I remember was the alarm wire running to the inside of the door and the other being a defective door jamb pin switch on either door, but again I don't want to see you go on wild goose chases.

I am the kind of guy that does not like to guess on symptoms because I feel my time is too valuable. If I have to fix something, I want to diagnose the problem correctly so I can just repair or replace the defective component. The door panels on these vehicles are very sensitive after age and if I don't have to mess with them I don't. Notorious for cracking the upholstery at the switch area on the arm rest, just taking them on an off makes the cracks bigger.
You did not tell me if resetting the alarm did anything or possibly you did not try it yet. If there was no effect using the key in the driver's door after locking them with the inner door button, I would highly consider either the alarm wire leading to the back of the outside door lock either fell off or is broken. That is just a guess and you should confirm with a factory manual.

Good Luck!  

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Rob Painter


Alarm system questions cannot be answered on this forum. These systems are not what I can answer. Without being physically at the vehicle and not knowing what kind of electrical service has been done on the vehicle, there is no possible way to give an accurate answer over the internet. My expertise is in Ignition/key based anti-theft systems. These issues include GM VATS (resistor chip in key blade) PASSLOCK (MRD)-ignition lock rotation based, no special ignition key and the PKIII Transponder (computer chip in key) systems. These systems are not alarm based and are integral with the starting of the engine. This is why I cannot diagnose alarm problems without physically looking at the vehicle: Alarm systems are a completely different annimal than ignition key/lock based anti-theft system. Many alarm questions come from vehicles 10 years old, and since older, many hands that had been involved over the years.I am an expert in all GM factory (ignition/key based)systems. Alarm system questions pose to many situations beyond my knowledge as to what has been done to the vehicle over the years. Some guy may have actually wired the stereo into the alarm system. Who knows? Over my past 30 years in vehicle wiring repair, I have seen unbelievable wiring disaters done by guys that consider themselves "mechanics." I have seen stereos and alarms intalled using surgical tape. I have seen modules burn up, un-fused circuits, wiring jambed between the doors and even lamp cord used for a starter kill. To answer alarm questions over the internet without examining the vehicle is like asking; What does it take to remove a dent?


Education/Credentials-ASE certified. 11 years with a GM dealer and 17 years with a repair facility dealing with only the repair of theft recovered vehicles.

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