Top 10 1998 Cadillac DeVille Questions & Answers

Sounds like they may have left something disconnected like the ABS/ Traction control wheel sensor, make them fix it!!

I have a 1998 Deville and both rear coil springs are broken.. It also has the air shocks that I dont think work.. Can I put regular shocks in and is there a after market coil spring out there for it ??

The most common overheating problem with the Northstar engine is a blocked purge line. It's job is to purge air out of the cooling system.
There is a small diameter hose coming from near the top of the coolant tank,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.If the hose is clear, check for blockage at the nipple on the tank.Or trace the hose back until you find the blockage.The hose goes in to the engine to a crossover and comes out the other side to near the thermostat housing,the blockage may be there.

The normal operating temperature for the Northstar engine is around 210 degrees.
The fans will not come on until the temp hits 225 degrees.

The thermostat in the northstar engine is located at the bottom radiator hose (unlike most conventional cooling systems).

The most common overheating problem with the Northstar engine is a blocked purge line(small hose).The purge line is designed to purge air out of the cooling system.
There is a small diameter hose coming from near the top of the coolant tank (not the cap) ,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.If the hose is clear, check for blockage at the nipple on the tank.Or trace the hose back until you find the blockage.The hose goes in to the engine to a crossover and comes out the other side to near the thermostat housing,the blockage may be there.

If the other end of your purge line is not connected to anything then that is the problem......it must be reconnected otherwise the cooling system is not pressurized.

I have a 1999 Cadillic Deville. The low Frefrigerant indicater come on after about 15 minutes of disconnecting the battery power. Each Time I reset the power the air conditioner comes back on for a while then goes out. I have taken it into the local auto repair place and they find no problem with the unit.
Could this be a intermittent connection to the computer. They have replaced both sencors and the problem persists. Where is the computer located on the car that handles this AC sensor message?

you can reset the computer by disconnecting the positive cable on your battery for 5mins. only be sure that your radio does not have to be recoded afterwards. refer to owners manual. resetting your computer will reset all codes even if your check engine light is on,,but depending what's wrong it will not repair everything! i hope this helps!

Hello: Check the fuses in the fuse box under the hood, drivers side also check the fuses in the trunk fuse panel on the drivers side. If the tail light fuse is open that will keep the instrument lights out also.

I suspect parasitic draw. All vehicles draw some power from the batteries when the car is shut off. Certain accessories such as clocks, radios remote door openers and alarms always need power. The normal power used is called parasitic draw.

It is always a very low draw so it doesn't run the battery down. If you install accessories like shortwave radios or plug things like inverters and portable refrigerators into the accessory socket and operate them too long without the engine running you can drain your batteries to the point where the engine won't start. If there is an electrical short in the vehicle or a malfunctioning accessory it could be drawing much more than its normal load causing a drain on the batteries. If you leave your door open and the inside lights stay on all night you could drain the battery down till the car won't start.

Here's also a good resource for your car specifically on narrowing down the cause of the drain.

Unless the vehicle has an after-market anti-theft system (in which case you will have to have it removed), the anti-theft system can be reset by placing the key in the driver door and turning it towards "unlock," then holding it there for 10 seconds or more.
If someone installed an after-market anti-theft system on the vehicle, you're pretty much on your own to disable it.

Check under the seat for broken wires. Forward and backwards is the function most used and causes the wires to bend back and forth. you may need to remove the seat for inspection or you may be lucky and see the problem just by raising the seat as high as it will go.