How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask MrDiag Your Own Question
MrDiag, ASE Certified Tech
Category: Pontiac
Satisfied Customers: 169
Experience:  16 Years of experience in Automotive Service Industry
Type Your Pontiac Question Here...
MrDiag is online now
A new question is answered every 9 seconds

Pontiac Bonneville: I have a 97 Pontiac Bonneville. Car wont

This answer was rated:

I have a 97 Pontiac Bonneville. Car won't crank. When key is turned to on position, radio and blower work, but none of the gages operate, nor any of the warning lights (seems like some of them normally light up momentarily on a normal start...) When key turned to crank the engine, I hear a click.

Battery is good. Cleaned connections

Security system has been disabled some time ago with the resistor put in the circuit to mimic the key resistor.

Checked fuses under the dash, and the big ones under the hood that seemed could be related to the ignition.

Could there be a bad relay?

Just trying to get some instructions for following the power path.

Hi, I’m a moderator for this topic and I wonder whether you’re still waiting for an answer. If you are, please let me know and I will do my best to find a Professional to assist you right away. If not, feel free to let me know and I will cancel this question for you. Thank you!

Customer: replied 5 years ago.

Yes, I'm still waiting for an answer. I was not in a hurry, so put the timing as such.


I appreciate your help.



Hi, My name is XXXXX XXXXX I am here to answer your Pontiac questions.

Please remember to only rate my answer when you are 100% satisfied. IF you feel the need to click either"Helped a little" or "I expected more", please stop and reply to me via the REPLY or CONTINUE CONVERSATION button with the issue you have. I will be happy to continue further and do everything I can to provide you with the service you seek.

Thank you,

OK, let's get started. In order to perform some tests, you will need a multi-meter to measure voltage.

The first thing we want to do is check for power to the 10 Amp PCM fuse with the key in both the on and crank positions. You can check this by touching the black or negative lead from your meter to a good ground and touching the red or positive lead to the tiny metal tab on the top of the fuse in the little recess. You want to check for power at both sides. You should have battery voltage there. This fuse feeds the Instrument Panel Cluster (IPC) and if power is missing at this fuse, it could point toward a bad ignition switch. To verify this we need to test further.

Please get back to me with the results of this test so we can proceed.

Customer: replied 5 years ago.


Checked the PCM fuse, and had just shy of 13V at both leads, in both the 'on' and the 'start' position. As an FYI, the PCM fuse was 20A.


For that matter, also checked the 60A ignition fuses, both leads were hot in both on and start positions.

OK, thanks for the info. Can you please verify the year of the vehicle. Both 1996 and 1997 are listed from what I can see on my end.

Also, please let me know if the security light is coming on at all and if it is staying on or flashing. I do realize that you mentioned the lack of warning lights, I am just confirming this one in particular.

The wiring diagrams that I am looking at are for a 1997.

The next thing to check is to see if there is battery voltage at the purple wire that goes to the small terminal on the starter with the key in the crank position. If there is power there and power at the big wire (battery cable) on the starter then the starter is probably faulty. Given the gauge issue, I am not so sure about this being the case, but we have to check to be sure there isn't more than one issue here. And since you here a click then the relay is probably working but once we know if the power is missing from the purple wire we can go further.

I will be logging off for the night and won't be back on until tomorrow afternoon. I will look for your response then, or if you need help sooner just let me know and I will opt-out and see if another expert can help you.


Customer: replied 5 years ago.

Sorry on the year mis-type. It is a 1996. The security light does not come on at all, nor any of the other lights or gages on the dash.


And, as I mentioned, we have cut the wire for the security system and installed the appropriate capacitor to mimic the key. This was done over a year ago. We've been driving the car that entire time, so should not be any issue with that.


If I'm not mistaken, the starter is accessed from underneath the vehicle. Just a bit difficult to get to without being up on ramps. I could jack it up with my floor jack, but just wondering if there are other things to check now that you know it isn't the security system.

You are correct, the starter is easier to access from under the car. It is located on the front of the engine, down low.

The reason that I was asking about the VATS system (security light) is because there is always a chance of the resistor that you put inline developing a poor connection, but this doesn't sound like your issue from what you are describing.

The diagram for the 96 car is slightly different. The same way that you tested the previous fuse, you can test the Airbag/Vats 10A fuse for power in the run and crank positions. This fuse feeds the circuit which closes the starter enable relay. The ground for the relay goes through the Park/Neutral position switch, then to the Pass-Key Decoder Module (Security Module). When the security module sees the correct resistance from the resistor it provides a ground for the starter enable relay.

Once you have checked for power at the fuse, next you can locate the starter enable relay. It is located under the steering column attached to the steering column support. It is a small square looking box with a connector.

Once you locate the relay, you can check for the following....
On Terminal C2, Purple wire, you should have power while key is in crank position.
On terminal C1, Yellow wire, you should also have power in crank.
On terminal A1, Yellow wire, you should have ground with key in run and crank positions.
On terminal A2, Purple wire, you should have power on in the crank position.

I do realize that it could be confusing with the same color wires, but if the connector terminals are not numbered, just remember, 3 should have power and 1 yellow should have ground. We need to know what is missing.

Let me know how it goes and we can continue from there. Thanks
I just want to add, it's a good idea to check all the fuses for ignition powered circuits to verify that they have power. I show a few options in my wiring diagrams based on what instrument package you have. If you have a fuse IGN OFF/UNLK 10A check it and also CHIME/CLSTR/RAC/MISC.

If you do not have these fuses in your model, then try to check anything that you recall coming on with the key. You can have power missing from some and not others, so checking all can help.
Customer: replied 5 years ago.

Back again.

No power at the Airbag/Vats 10A fuse (position 2E). It is on the inside fuse block.

Also no power on the entire row 1:






Confirmed this several times by referencing the radio fuse which I know was live as the radio worked, and quit when I pulled the fuse.


For that matter the other fuses were all live on the inside block, except the INTERIOR LPS.


I checked all the maxi fuses for power - they all looked good. If there was a specific one in a circuit in question, would be glad to check it again.


I haven't checked the relay yet since we don't have power at the Airbag/Vat fuse.




Thanks for your patience to get to the bottom on this one.

Customer: replied 5 years ago.

I just realized I didn't check the Airbag/VAT fuse in the crank position, only in the run position. No power in run position.


Where is the Park/Neutral position switch? Seems like the next logical thing to check.

OK, I mis-typed, the airbag/vats fuse should only have power in crank position.
When checking for power at the other fuses, especially the IGN/Chime Clstr fuse, be sure that the key is in on. If you have no power at the Ign/Chime Clstr fuse then we need to see if there is power coming from the ignition switch itself.
The ignition switch would be my first guess with this type of failure and the most common cause. The Park Neutral switch only interrupts the ground side of the relay, so since you are missing power (if I understand correctly) then we need to check for power to and from the ignition switch.
The ignition switch is located on the steering column also. I will include a picture. Once you locate the switch, you need to test for power at the red wire going into the switch.
This is fed by the 60A IGN fuse under hood. According to my diagram you should have 2 fuse panels under the hood and each has a fuse that has IGN in the wording, we are interested in the IGN SW fuse that should be in the Right Hand fuse block. You should also have power at several wires coming from the switch with the key in the run position.
The main one to check is the Orange for now and also check the yellow while in crank position as this feeds the starter circuit. If you are getting power in on the red and power is missing from any of the feed wires coming out then the contacts in the switch are bad and the switch should be replaced. Let me know what the result of the testing is.
Thanks. Also, I might be offline for most of the day today, with it being a holiday. I will check in when possible. If I don't respond back today, I will tomorrow.
You will need to remove the plastic panels that are under the steering column. This can be done by simply removing the screws, which are usually a 7MM.
MrDiag, ASE Certified Tech
Category: Pontiac
Satisfied Customers: 169
Experience: 16 Years of experience in Automotive Service Industry
MrDiag and 2 other Pontiac Specialists are ready to help you
Customer: replied 5 years ago.


Happy 4th of July. Frankly, I was surprised you were on at all today. I figured you'd have the day off and be celebrating.


I dropped the panel held by the three 7mm screws. From what I gather, the ignition switch is up in the cowling near the key switch.... not real obvious on how to check the power on the switch as you describe.


Any pointers in that regard?


Are you sure this dialogue isn't going longer than it should based on the use of this forum? I certainly appreciate your help, but don't want to abuse the intentions of the service.






PS - in checking this again tonight, it shows as closed. Not sure why. Was hoping to finalize the root cause of the problem before officially closing.


Happy Independence Day to you too! I am taking off, but I am able to check in for responses, and since we were still in the middle of figuring things out, I wanted to respond back. It is ok that this post is getting a bit lengthy as it is my goal to provide you with the service that you are seeking. I want to help you get to the root cause of your problem. Sometimes this can take a while as we go through different testing options. And you are not abusing the service.

I am not sure why it shows the question as closed, it might be because you have already submitted your rating. No worries, we can continue to work on this and communicate for as long as you still have questions about this issue. Thanks for the excellent rating also.

As for the ignition switch, it is on top right of the column and has a rod that goes from it to the key cylinder.
In case you have only removed the one panel that goes down by your feet, you also need to remove the knee bolster panel that is near your knees and under the column. Once you have that removed, you should see a bunch of wires that run along the column and go to a rectangular connector with a bolt in the center. The high and low beam switch which is on the opposing side of the column shares this connector. Follow the wires from the ignition switch to the connector and probe the wires at the connector to check for power with the connector still connected. You will be back probing the wires where they go into the connector. The wires that you will be testing will be the heavier gauge.

I hope this information helps. Let me know how it goes, and I will respond back as soon as possible.


Customer: replied 5 years ago.

Finally back at it...

I have power at the red, orange, brown, green in the run position.


Also have power at the yellow in the crank position.


The pink wire has no power in either the run or crank position.


Does this help?

Yes it does in fact help. If my diagrams are correct, the pink wire coming from the ignition switch feeds the fuses that are missing power in that row. If you have power going into the switch, which you do from what you have described, then there should be power at the pink wire.

I would replace the ignition switch. Once you disconnect the switch, you will see the metal rod that operates the switch. You can tape the rod to the column once the switch is out of the way, so the rod does not fall out of upper end of the column. Let me know once you have replaced the switch.

Also, it is usually a good idea to disconnect the battery while replacing electrical parts such as this.

I hope all goes well, and look forward to hearing back from you.
Customer: replied 5 years ago.

Got the new switch installed. Gages work, and the starter cranks. Good work.


One last thing I'm chasing:

When I crank the engine, the starter is somewhat intermittent, like there is not a good connection somewhere. I've never experienced this. Do you know what might be the source of this? At first I figured it was the adjustment of the switch as it has slots in it. Figured the position to activate the starter was marginally getting depressed. I adjusted this in the slot as far as it would go to push the switch in the right direction, and still had the same performance.


Just to clarify, by intermittant, I don't mean that sometimes it cranks, and sometimes it doesn't. When you turn the key to start it, it like the starter is going on and off, in a somewhat random way.


I'm glad that you are making some significant progress.

For the next issue that you are describing, I would start by making sure that the battery is fully charged.

Next, locate the starter enable relay which is under the steering column and is attached to the column support. It is a small square box with approx. 4 wires going to it. You should have 2 yellows and 2 purples. When cranking you should have power on 3 wires, (I will reference terminal designation in case it is marked) C2 Purple, C1 Yellow and A2 Purple.

You should have ground on A1 Yellow.

If all of these wires read correctly and you are experiencing the issue, then I would go right to the purple wire on the starter and see if you have constant power there and on the large terminal which is the positive battery cable. while cranking. If so then the starter is most likely the problem.

If you have intermittent loss of power on:

C2 Purple, this wire is the power for the trigger side of the relay and comes from the Airbag Vats fuse. This fuse is fed by the Yellow wire from the ignition switch. There have been cases where an aftermarket ignition switch was bad right from the start.

C1 Yellow, this is from the same circuit which is fed by the Yellow on ignition switch.

A2 Purple, This is the power that comes from the starter enable relay and goes to the starter solenoid. If this is the one with the loss of power at times and the others are OK, then the relay itself is bad and should be replaced.

The next wire A1 Yellow, is a ground which goes through the Park Neutral switch on the side of the transmission on drivers side kind of below the master cylinder, then to the Pass Key Decoder Module. If there is a loss of ground here then I would start tracing back starting at the Park Neutral switch.

I doubt it is the ground side.
Customer: replied 5 years ago.


All is back running.

Thanks much for all your help!!!

My pleasure. Glad it is working.

Related Pontiac Questions