1999 cadillac obd port location

can't find exact location for you but here is a link to a caddy forum , someone there will know
1990 Deville BCM ECM communications problems Cadillac Forum Enthusiast...

Hi Gary, I'm not sure if you're still looking, but I found your car's obd if you're still looking for it: http://bit.ly/18FpSWz

the heater core in a 1998 Cadillac is very tricky to replace.
start with getting a pressure test to determine where the exact location of the leak is, it may not be the heater core.
if you do decide to pull the dash apart to change the core make sure the battery is disconnected for at least an hour to allow the airbag system to discharge.

sound to me like a bad ignition coil, a common failure on these year of caddy

Under the dash on the drivers side.

Follow the top radiator hose to the engine. Remove that end of the hose and then remove the thing the hose connects to. The thermostat is behind that.

u dont have an obdll system u have an obd which is a 12 pin port under dash by steering column

I believe it is located behind the glove box... I had an older Caddy and that's where that one was.

thermostat is located on intake.just follow top radiator hose.there might be a cover over it that needs removing.

Maybe this will help . although this is from a 1997 Caddy.


Cadillac DeVille Engine Coolant Temperature (ECT) Sensor Location