Going down the rabbit hole Electrical Issues
 

Just purchased a beautiful '03 CTS with 12,000 miles on it that has some electrical issues and I am hoping they are all connected with a root cause. I have tested all the fuses and everything seems good. I will start with a list of things that work.

Things that work:
Headlights, taillights, turn indicators, brake lights, sunroof, power seats, climate control blower and associated controls and I think the horn works too, I will check it this morning.

Things that don't work:

Everything else
cant take the key out of the ignition
cant take it out of park
car doesn't star, the starter doesn't do anything
No windows, locks, mirrors, radio, dome light, trunk opener, gauge cluster

When I turn the key to on I get a check engine light
The odometer doesn't come up, I had to run a carfax to verify mileage.


I have read about a bcm but have not found any information on its location or what powers it. If you have any information on this please let me know.

This was purchased as a project for me so please dont say take it to the dealer. If it comes to that I will but as a last resort.

Chad

Not sure if this is your case... but when we were working on my cts... i yanked a relay out of the fuse box under the hood and experienced all the same issues. put the relay back in, disconnected battery and hooked it back up, and good.. try it. you might have a bad relay.

Do you remember which relay? I read on the forum about corrosion on the connector under the passenger seat due to moisture under carpet. Today I peeled the carpet back and it is wet under there. Tomorrow I will try to remove the seat to get to it. Can it be that easy??

I tested every fuse and they are all OK
tested every relay and all good

The horn does work, and the windshield wipers also work but everything else is non-functional.

Removed the passenger seat and didn't find any connectors with corrosion

the connection in that area that usually corrodes is where 5 fat 10ga red wires/with white stripes... meet up in a copper connector.


how did you test the relays?

I will verify that I checked this connector.

To test relays

1) remove from car
2) look at diagram on side of relay
3) apply 12v to coil leads If I remember correctly it is posts 85 and 86 (look at diagram)
4) verify no continuity between post 30 and 87 when no voltage applied to coil and continuity when voltage applied to coil (again look at diagram to verify post #'s)

Some relays have a normally closed post between 87a and 30 when no voltage is applied to coil.

Now I did test these with no load on them I suppose it is possible that they may test differently when loaded.

Found more stuff that works

Hazzard lights
fog lights

Anybody know how to get it out of park, it would be nice to move it from where the tow truck dumped it, maybe put it in the garage.

Major Progress!!!!!
 

Tonight I discovered that if I remove the 15A fuse that powers the drivers control module EVERYTHING WORKS!!!! with exception to the drivers door.

Now, withe the 15A fuse pulled for the drivers control module in the drivers side rear fuse panel the only things that do not work are as follows:

anything on the drivers door (windows, mirrors, trunk, locks)
Keyless entry / all remote fob functions
passenger side rear window will go down but not up???

Everything else works as it should, I can even drive the car now. It runs and drives perfectly but my mileage was not as advertised. Supposed to be 12,000, it is actally 32,000.

So what do I need to do, Replace the drivers control module??

Is it true this will need to be programmed?

Feeling much better about my purchase even though my mileage was misreported,

Chad


P.S. even with the passenger seat removed and the carpet out, I still can't find the large 5 red wires in a connector???

Update
 

I checked out the door control module and the drivers module works in the passenger door fine, the passenger module in the drivers has the same symptoms.

If I unplug the window switches in the drivers door, everything works correctly (with exception to the drivers door). I am going to the dealer to I opened up the window switches and found some corrosion inside of it. I am going to pick up a new window switch today from the dealer.

Crazy, plug in the window switches, car is dead unplug and it instantly comes to life.