2005 cadillac cts wont crank

Won't start how ? When you turn the key to the start position does the starter spin the engine ? Or not ? This would be a no crank - no start condition ! Or when you turn the key to start the starter spins over the engine but it doesn't start an run ? This is a crank - no start condition . Both have very different diagnostic testing procedures ! An what won't say anything ? Is there a car an padlock symbol lit on the instrument cluster ?

It's not the crank pulley , it's coming from above an leaking down around the crank pulley . It's actually the water pump which is right above the crank pulley .

private sale or from a used car lot if from lot call and advise should have a limited warranty ---if private call and ask about non start --try to get vehicle scanned and check for any codes previous may have cleared codes to make sale --check fuses/relays -if have starter fluid give shot if starts check fuel pump -possible fuel filter-if pump good will need to check ignition system ,check for spark,and or certain sensors like the crank position sensor------- the following post is from caddyinfo forum Subject: Multiple Electrical System Malfunctions, Engine Will Not Start, Engine Will Not Shutdown, IP Gauges/Lighting Inoperative, Radio Inoperative, HVAC Display Erratic, Loss of Rear Door Functions (Inspect Both Rear Door Harnesses and Repair, if Necessary)
Models: 2005 Cadillac STS
Built Between and Including VIN Breakpoints 50112423 and 50133076
Attention: This inspection should be performed on all vehicles currently in your inventory prior to sale or delivery.
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Condition
Some customers may comment on one or more of the following conditions:
• Engine Will Not Start
• Engine Will Not Shutdown
• IP Gauges/Lighting Inoperative
• Radio Inoperative
• HVAC Display Erratic
• Loss of Rear Door Window/Lock Functions
These conditions may occur intermittently.
Cause
These conditions may be caused from the rear door wiring harness being misrouted causing the harness to contact the metal door bracket. This contact may cause a rub through to the wires enclosed in that harness.
Correction
Inspect both rear door wiring harnesses. Repair any damaged wires and reroute harness to correct location. Use the procedure listed below.
Make sure the ignition is off.
Remove both the rear door trim panels. Refer to the Side Rear Door Trim Panel Replacement procedure in the Doors sub-section of the Service Manual (SI Document ID #1465575).
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2005 STS electrical problem NO START

Does the engine crank over and not start or does the engine not turn over at all?

I had something similar happen on my 2004 CTS. The car would not crank, and I recall the security light was on the dash. The key could be turned off, but not quite far enough to be removed.
The key can be removed by sticking a small pin or screw driver in a hole under the steering column... maybe 2 inches from the actual steering wheel. I recall there is a small cover or plug in the hole that needs to be removed.
You can let it sit and occasionally try to start it. My did start once more.
I ended up having it towed to the GM dealer and they replaced the ECM for about $500? That took care of it for a couple years, until I recently sold it.

check your fuses under dashboard..

probrably ignition key cylinder is failing n theft loc up the car

How do I reset my alarm in cts 2004

Sounds as though the chip has been damaged in some way. Only solution is to take to dealer for new complete key.

Sound like your ignition is gone bad.