1999 Cadillac DeVille - Page 6 - Answered Questions & Fixed issues

Sea Foam will clean your engine - intake, injectors, combustion chamber, etc. "Hi Test" will not.

Higher octane fuel actually has higher resistance to exploding. High compression engines need higher octane to prevent 'pre-combustion' or detonation (explosion). Diesel engines do not have a spark plug and rely on diesel fuel detonating due to the very high compression (sometimes 2.5 times what you see in gasoline engines). When octane is not high enough, just the compression stroke will cause the gasoline to detonate on its own prior to the spark plug firing, causing pinging or knocking.

So, DON'T USE 'HI-TEST' gasoline to clean out your engine - it will NOT perform that function for you!!!

1999 Cadillac... | Answered on May 21, 2015 | 123 views

I think an auto parts store or dealer has to program it.

1999 Cadillac... | Answered on Jan 29, 2015 | 117 views

Do you have the dash light dimmer control turned off by mistake? If not test the dimmer control with a volt meter.

1999 Cadillac... | Answered on Jan 26, 2015 | 231 views

Already answered this.

1999 Cadillac... | Answered on Jan 24, 2015 | 35 views

check all fuses

1999 Cadillac... | Answered on Jan 22, 2015 | 41 views

Look under the bottom of the back seat, behind the carpet coming up from the floor.

1999 Cadillac... | Answered on Jan 21, 2015 | 51 views

Not much to a tune up on these vehicles; spark plugs, spark plug wires, air and fuel filters, and some 'good' fuel treatment.

1999 Cadillac... | Answered on Jan 21, 2015 | 72 views

read your obd computer. probably need to change one of your wheel hubs. the sensor is an integral part of the hub/bearing assembly.


1999 Cadillac... | Answered on Dec 24, 2014 | 259 views

Look in the engine compartment relay center.

1999 Cadillac... | Answered on Dec 22, 2014 | 160 views

have you tested the car battery , sounds like that could be low on AMPS ,( volts are very different ) , then check the alternator charge rate is ok

1999 Cadillac... | Answered on Nov 26, 2014 | 49 views

No fuse.These seats are protected with relays and a seat module.The module is under the drivers seat.There are 3 connectors and it would be hard to check all these wires for power to the motors.First look under the seat and make sure none of the connectors came apart under the seat by something that might have been left or rolled under it.The 2 main ones you can check are the connector 2 terminal C and connector 3 terminal A.C is a black wire which is ground and A is a red wire which is the feed power wire.Connector 2 is green and 3 is black.If the ground and power wires are good then you could have a bad drivers seat module.What I would do is go to the salvage yard and find a used module to try.Good luck.

1999 Cadillac... | Answered on Mar 04, 2016 | 3,400 views

It's getting a power surge or short from somewhere. Most likely the wiring harness that runs along frame rail has been damaged. The other option is a bad ground. I would start by tracing the wiring harness for the fuel pump and pay close attention for damage

1999 Cadillac... | Answered on Oct 11, 2014 | 74 views

Take out the back seat.

1999 Cadillac... | Answered on Oct 09, 2014 | 17 views

Sounds like a circuit beaker in the front fuse block overheating and opening. Check for the one supplying these systems and replace it.

1999 Cadillac... | Answered on Sep 28, 2014 | 27 views

It sounds like you have either a low pressure cutoff switch that is faulty or connection at the switch/wiring. The computer will only see the fault while it is operating and it will only set the code after 2 consective faults. Make sure you have the system checked by a professional to make sure pressures are correct in the system first.

1999 Cadillac... | Answered on Sep 27, 2014 | 100 views

Antitheft or Security system failure is a common problem on GM vehicles. Every time you put your key in the ignition, the vehicle's security system reads the signal from your key to make sure it is OK to run. When it receives the "correct key" signal, the security system allows the starter to turn over, and/or the fuel injectors to function and your car works like it normally does every day. If you were to use a different key, or try to hot wire it, the system would shut down these parts of your car, thus making the vehicle completely immobile. This is GM's way of preventing vehicle theft. The problem is that the system is known to fail quite commonly. It has been failing consistently for around 30 years. When it fails, two things can happen. First, you turn the key and nothing happens at all. Lights work, radio works, windows work... just not the starter that you need to start the vehicle. This is a "starter immobilizer". Second, you turn the key and the vehicles starts just fine, but then stalls in 2-5 seconds. This is a "fuel immobilizer". It literally cuts off the fuel injectors and stalls the vehicle to immobilize it. These are normally, but not always followed by a light on the dash that says SECURITY or ANTITHEFT. These lights are to inform you of the system's failure to collect the information it needs from your key to the computer. If your security/antitheft light is on, odds are you will be stranded soon, if not already. Remember that the security system controls the security light. If the system is failing, the light may never warn you of the failure. There is a lot of info on this site that you can read up on. http://vatspasslockpasskeysecurityhelp.yolasite.com/

1999 Cadillac... | Answered on Sep 22, 2014 | 198 views

if you look at the top part of the parking brake you will see a lever take a screwdriver and pry up on the small lever and it should release

1999 Cadillac... | Answered on Sep 19, 2014 | 177 views

Sorry mate, I dont know what this Gas cap is, could be the fuel filler cap, could be the car runs on LPG and it is a cap on the Gas charge line.

1999 Cadillac... | Answered on Sep 06, 2014 | 199 views

Call a Caddy Dealer -they should know how.

1999 Cadillac... | Answered on Aug 25, 2014 | 21 views

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