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FIXITMAN
FIXITMAN, Master Technician
Category: Cadillac
Satisfied Customers: 17143
Experience:  ASE MASTER CERTIFIED, AA DEGREE AUTO/DIESEL TECH.
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I have a 2007 Cadillac DTS that doesn't crank but radio,

Customer Question

I have a 2007 Cadillac DTS that doesn't crank but radio, lights, and other stuff come on it just don't crank. I hoping I can get some advice or tips on what can I do or check with my meter. I think it a bad ignition switch base on what I have check.
Submitted: 1 year ago.
Category: Cadillac
Expert:  FIXITMAN replied 1 year ago.

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.

Customer: replied 1 year ago.
Hi Bobby thank you for you help and response. Yes I think it is the switch as well because I can jump the starter by jumping the S terminal on the starter with a jump wire by taking it to battery positive and the engine will spin but it won't crank because I think the computer control ignition and the fuel pump by turn it on when the key is in the on position. Also I did what you said but when I try starting it nothing happen but the voltage stay the same. On the starter relay I know I suppose to have two power feed I only have one feed and that 12 volt without the key on and I have nothing on the other terminals of the starter relay when the key is on which I suppose to have 12 volt when the key is on one of those terminals.If you look at the ignition switch diagram I have 12 volt on the ignition 1 voltage pink wire when the key is on and I have battery positive voltage on the PK/YE wire when the key is not switch in the on position which is correct right? Also on the BN Wire which is Accessory Voltage I have 12 volts when the key on and off. Then on the WH wire which is the Off/Run/Crank/ voltage when measure with the voltmeter it reads 4.85 or 4.95 volts when the key is in the off position and with a test light it light up when the key is in the off position but not in the start position. That WH/BK wire is the same reading as the WH wire. I just want to make sure it the ignition switch and nothing else like a wire broken or something. Tell me what you think and what else you think I should do?
Expert:  FIXITMAN replied 1 year ago.

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?

Customer: replied 1 year ago.
the brn and pink wire does have full battery voltage in the run position. The brn wire have full battery voltage in run and when the key is off. The pink wire just have voltage in the start run position. Well the sound of the click relay sounds like it coming from the rear full box not from the from unde the hood fuse box but I do hear a clicking of a relay when trying to crank it.
Customer: replied 1 year ago.
I might just go ahead put a ignition switch in it to see if that fix the problem it nothing but $20 buck at the part store.
Expert:  FIXITMAN replied 1 year ago.

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.

Customer: replied 1 year ago.
pull the rear fuse box up and check the connections? I really don't want to put a ignition switch in this vehicle and it not the ignition switch. I don't understand why on that pink wire why it don't have battery voltage at the Run/crank relay which the switch is in the start position but at the switch it does have battery voltage when the switch that my other feed. Also I know I have suppose to have two power feeds but I'm only have one at the replay which is the PK/YE wire. I have battery voltage at the ignition switch which the switch is off and at the relay which I know that is right.Looking at the diagram and the Starter S terminal Connector I see a brown wire going to the relay box but it don't tell you in the diagram where that wire going to. I can take that S terminal to battery positive the motor will turn but won't crank because that circuit control other systems. Do you think that G112 ground is bad because by looking at the diagram the computer provide or want to see that ground to receive signal to start the vehicle. What you think?
Expert:  FIXITMAN replied 1 year ago.

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.

Customer: replied 1 year ago.
I do have voltage on the pink wire when the switch is in run position and trying to crank it.
Customer: replied 1 year ago.
That ground at G112 is behind the manifold right? It hard to get back there to check it.
Expert:  FIXITMAN replied 1 year ago.

Yes, it is hard to get to. Did you happen to check the relay I mentioned to see if it was clicking?

Customer: replied 1 year ago.
I'm sorry for late reply just been working but I did check but I don't if that the relay or what. I kind of took a break from it.
Expert:  FIXITMAN replied 1 year ago.

No problem. Let me know once you can check this and get back to me.

Customer: replied 1 year ago.
No I don't hear no relay clicking. You don't hear nothing. Like I said before only thing coming on is the light, radio, and etc. What you think?
Expert:  FIXITMAN replied 1 year ago.

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.

Customer: replied 1 year ago.
I did switch it with another relay but still the samething. Test what fuse terminal? The ignition fuse?
Expert:  FIXITMAN replied 1 year ago.

No. Pull the relay and test the metal terminals that it plugs into.

Customer: replied 1 year ago.
I did that only one terminal has power when I test it with the test light. Also I did it when the key is on as well only one terminal has power when the key is in the on and off position. That both relays the crank relay and the crank/run micro relay.
Expert:  FIXITMAN replied 1 year ago.

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.

Customer: replied 1 year ago.
This is a common issue with these Cadillac's I don't think it the BCM it has to be a ground problem or something in the ignition switch. Too many people having the same issue on internet with these Cadillac regardless of the model. I believe it has to be a poor ground or something in the ignition switch. It has to be a way where you can jump or apply power to a wire or wire to the ignition to make this car fire up or something instead taking a jumper wire straight to the starter wire. It just crazy. It seem like nobody knows the problem and it common with these vehicles. Somebody know.
Expert:  FIXITMAN replied 1 year ago.

Did you install a new factory ignition switch?

Customer: replied 1 year ago.
No not yet. I want to do some checks at the BCM first to see if the BCM is getting the right voltage an grounds at the right wires. Also, how do you remove the lock cylinder where key go into? I see the two bolt to unloose the ignition switch but I can't get the lock cylinder remove.
Expert:  FIXITMAN replied 1 year ago.

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.

Customer: replied 1 year ago.
you saying I can't back probe the terminal at the BCM with a Multimeter to see if the BCM is reading samething at the ignition switch. Also, I have to remove the steering wheel to see that lock pin you are talking about?
Expert:  FIXITMAN replied 1 year ago.

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.

Customer: replied 1 year ago.
I have the column covers remove I just don't see that pin you are talking about. I know the pin you are talking about I don't see it. I done one before never done one a a cadillac. Is that pin on the side or on top of the ignition cylinder?
Customer: replied 1 year ago.
Also I will do everything later on today and let you know how things turn out
Expert:  FIXITMAN replied 1 year ago.

The pin should be located right on top of the lock. It will just look like a hole.