Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
Hello, my name is Bobby. Thank you for the question. Almost every time this is a failure in the switch. It is common on this car. I would take your meter first though and see what the battery voltage is. It should be over 12.5 volts. If it is then see what it does when you try starting it. If it barely drops then it is more than likely the ignition. If it drops below 10 volts then it may be a bad starter.
The white wires have the right voltage. Can you tell me if the BRN and the PNK wires have full battery voltage when the ignition is in the run position? If not then the switch is bad. Also, is there any clicking from the RUN and the RUN/CRANK relay when trying to start it?
It seems to be testing fine but you can give it a shot. I would also double check the tightness of the connections at the rear fuse box as I have seen connection issues there.
There is only one power wire to this switch. The white wires will only run reference voltages of 5 volts or less. Does the run/crank relay click at all when you try starting it? If not and if you have voltage to the pink wire when trying to crank then that ground at G112 on the transmission can be bad.
Yes, it is hard to get to. Did you happen to check the relay I mentioned to see if it was clicking?
No problem. Let me know once you can check this and get back to me.
We need to see why that relay is not clicking. I would either switch it with a similar relay as a quick test or turn the ignition on and test the terminals in the fuse box and see which ones have voltage. Two of them should.
No. Pull the relay and test the metal terminals that it plugs into.
Thank that means that the run/crank relay is not getting power to turn on from the body control module. Most of the time this will occur when the module goes into theft mode, but it would give you an theft light on the dash. The BCM itself may be failing.
Did you install a new factory ignition switch?
With testing the BCM you would need a scan tool to see what the data is that it is getting. To remove the lock cylinder you will turn it to the start position and press the small metal pin on the lock cylinder with a bent metal dowel to release it.
With the column covers removed you should be able to access the pin. There is no reason to remove the steering wheel to do this. As for the BCM you can test the pink and the brown wire there to see if it is getting voltage from the ignition switch.
The pin should be located right on top of the lock. It will just look like a hole.