I have a 1998 Cadillac Deville. The battery keeps dying. I have replaced the alternator
, battery, battery cables, battery posts, and disconnected the aftermarket stereo. It still dies... I checked all of the fuses, even the ones in the trunk... still dies after about 12 hours. so, i checked out this post:
Re: 1998 Deville, weird electrical problem
You are on the right track with the BCM(PZM), on the Deville if a Aftermarket radio is installed without installing the original in the trunk it causes all kinds of weird things to happen. The problem is it is very random and will drive you nuts trying to correct. Your model Deville has a deep sleep mode which is controlled by the bcm, it also has a battery saver mode as well, both of these could be combining to produce this loss of memory etc. If you do a search there is a link that is entitled for those who own a 97-99 Deville in the audio section, it covers what is happening to you and how to fix it. My BCM did the exact same thing on my Deville as yours is doing.
just came back to say what he said, figured it out, here is some more info
all u ahve to do is run the two databus (i believe purple) wires to the trunk and find power and groundings in the trunk or 4 wires if u want chime. two databus and two speaker wires to the trunk... here is a posting i copied.
OK, after sifting through this thread I started getting angry at all the mis information. I went through this all durring the summer. I replaced the stock unit and all the speakers. The "sleep mode" you are expirenceing is because the stock unit has to remain wired in the car or the car is going to go into lockdown mode. You dont need any fancey harness, just the standard harnesses, and a spool of wire. The stock stereo is going to have to be relocated to the trunk. I put mine next to the wheel well. You will have to run power, ground and the databus wires to it, and a speaker if you want chimes. the data bus wires are pins F6 and E6 on the harness. Ground the unit on the body and run the power wire from the 12gauge wire coming from the radio fuse in the fusebox located in the trunk. As for the aftermarket unit. The stock wireing is not a constant 12v and there is no accessory wire. for the 12v I ran a wire to the fuse box in the trunk to one of the thicker 10gauge wires. You will need to test this with a multimeter to make sure its alwasy 12v, even when the car is off. The accesory wire i ran into the power window circuit (blue 12 gauge wire). This is optimal because its close and it retains power after the car is off untill the door is opend or 10min. This is just a quick overview. If you have any question or would like me to go more in depth, PLEASE PM ME, I will be very happy to help you. (Note: I spent a good 12 hours on this my first time, Its not to difficult, but time consuming)
after reading this post, I reinstalled the factory stereo. same issue. please help...