I recently bought an 03 cadillac CTS, it did not come with keyless entry and the dealer said my stock module was dead. So i called a local audio shop and they want over $400 for the keyless entry or $200 to install one i get somewhere else. So instead of paying them to put another stock one in or having the audip ship rip me a new one with no lube i was wanting to get and install an aftermarket one with keyless entry and maybe remote start. I have been searching and looking around and cannot find how much of a pain in the ass these things are to install. If anyone could help me out and tell me a little about the install i would much appreciate it.
The difficultly of install is related to your desire & ability.
A few questions to ask yourself.
Do I have the basic tools for automobile work ( sockets, wrenches, torx drivers, screw drivers, etc ) ?
Do I have a soldering iron suitable for automotive electronics and can I solder?
Can I work in tight / confined places?
Do I have and can I operate a Digital Multi Meter? All wires should be checked & confirmed before install.
Do I have the time & money to buy supplies like cable ties in various lenghts, quality electric tape,
heat shrink tubing in various sizes, proper anti-mar trim tools for removing door and dash trim panels, etc?
Can I read and understand the install guides and wiring charts necessary?
The remote keyless entry part of the job will require removing the drivers door inner panel to access the lock module. That also means running the wires from the door back into the car. Sounds easy but to do it properly so it will last many years is the goal.
The remote start part of the job will require a bypass module to allow the car to start without the ignition key.
These modules must be attached to the car and the remote start unit and programmed to the car in accordance with their install guides.
Figure on about 6 hours of actual car time and almost that amount in procurement / research / prep time. Also be aware that units from DEI, Compustar and others come with a warranty "IF and only IF" they are installed by a dealer. Additionally, as a DIYer you will find it difficult to get any tech support from those companies.
Because of the door locks and the PassKey3 immobilizer, I would use the iDatlink ADS-DLSL GM1 bypass module with a quality remote start w/keyless entry system. This bypass module will control the doors, trunk, and car alarm with just one easily accessable wire connection to the car. Cost is about $50 and it would save a lot of time locating and connecting to the cars wires.
Here are a few links to get you started.
Bulldog Security for wiring charts and basic DIY remote start systems: https://www.bulldogsecurity.com/bdnew/vehiclewiringdiagrams.asp
AudioVox for wiring charts: https://techservices.audiovox.com/Login.aspx Membership is free.
DEI for bypass modules: https://www.xpresskit.com/VehicleCompatibility.aspx?p=-1&year=2003&make=Cadillac&model=CTS&ps=1&s=0
Fortin for bypass modules: https://ifar.ca/en/vehicles/cadillac/cts/2003/
ADS iDatalink for bypass modules: https://www.idatalink.com/helpdesk/
DEI Ready Remote DIY systems: https://www.designtech-intl.com/diy.asp
Good Luck!
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Soldering is fun!
Doesnt look like a hard install. The 12v constant has to go to the battery, so make sure you fuse it properly. If you use an XK01 for a bypass that will take care of the door locks too which will save you some time. If you have a decent knowledge of 12v you should be able to do this just fine. Do yourself a favor and solder don't t-tap things.
I have an 03 cts I put a viper 791xv in a number of years ago along with the xk01. It's not a difficult install. My only complaint was that there was a delay with the xk01 when locking with the remote. I recently ran the doorlock wires into the door through the molex and boot and on up to the switch. Now there is no more delay. There is a nice grommet to run wires through the firewall to the left of the brake pedal. There isn't much on the passenger side where the battery is because the cabin air filter is located underneath/behind the battery tray. You can take out the battery remove the tray and all of the trim and drill a hole if you want as I've done this to get power wire for an amplifier. It's kind of a b**** though. good luck
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Advanced
The door panel comes off very easy in that car. And you can run the wire thru the boot easily too. These no molex plug to deal with. You can get the FAD at the keyswitch wire. And you can get the latch (door trigger) to shut down the autolamps there too. So run 4 small wires into the door and you'll get lock/unlock/FAD/Door trigger all there.