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Cadillac Repair/1979 cadillac seville


Hi Rob,

 I just bought a cadillac like 2 months ago.. It was doing just fine.. I went togo get gas pulled up and threw some gas in hopped back in and it wouldn't even try to turn over.. All the lights worked and everything.. So i asked for a jump and still nothing.. So i took my starter out and had it tested nothing wrong with it or the sillinoid..  I put it back in still wasn't working so i jump the starter.. That got it started so i proceeded to drive to my house and about five minutes into the drive I noticed that all the lights stated getting real dim. Then it started to back fire when i was accelerating. So over the next couple of days ive tried a new battery, battery cables, cap and roter, ignition coil, and ignition switch.. It still wont turn over or even try. I'm running out of ideas.....This Seville started its life as a diesel and th owner before me converted it to the v8 carb.          

         Any ideas would be greatly appreciated
         Thanks   AJ

         Any ideas would be


The first problem is that it is a conversion to gas. Who knows what someone did here, I think I can help you though. Guessing is the worst thing in the world and time consuming and like in your case cost a lot of money to replace replace perfectly good parts.

It sounds like you have more than one issue here.

The lights dimming and the backfiring is from a charging system issue. When running only on battery power, once down to 10 volts, the engine will lose ignition and battery power and eventually the car will just stop running. You need a test light, and  multi meter. These pieces of equipment are probably going to cost less than 50.00 at a parts store. You already spet a tone of money guessing, and these items will assist you all the time. The battery may be junk now. We simply don't know yet.

The first thing to do is charge the battery and hopefully it holds a charge. With the test light, clip the alligator clip to a ground and put the test light in the big red wire on the back of the alternator. Test light should be bright. Next, check the fuses. You may have a burned out gauge fuse. This would prevent the alternator from charging. If that is good and you can't get the engine started, there is a good chance the alternator is bad. Don't change it yet though. Follow the negative cable for the body down to the frame. Remove bolt. scrape the frame so there is bare metal. Reinstall bolt. See if the engine will start. If it does, use the multi meter set to volts by connecting the leads to each battery terminal. If running, the voltmeter should read 13.2 volts or above. If only 12 volts, the alternator is junk and you need a new one.

If the engine starts now, the problem was in the body ground. If it does not crank yet,then you need to put the test light on the purple wire of the solenoid and have someone and see if you have power. If not, its important I know something. When you say you changed the ignition switch, did you. Many think the ignition lock cylinder is the ignition switch and it is not. The electrical ignition switch is under the dash and on te top of the steering column.

You will need to see if you are getting power from the ignition switch when lock cylinder is in start position. If power is there, but not the solenoid, tere is iether a break in the wire o the fusible link is faulty. To check for a blown fusible link, pull on the purple wire. If it seams rubbery, you need o replace the fusible link. One last thing. You need to see if you even have constant power to the ignition switch. If not, you will need to trace the wiring and find the break. One way or another, all this will fix your vehicle.

If it all works out which it will, if you are real happy, possibly you would donate something. There is no obligation, but times have been extremely rough for me and any donation would help me at this point. Thank you.

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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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