Expert: Sean Halliday - 1/12/2009

Question
QUESTION:
Need Help! Grandson needs car to start college this month and I want to give him this car.  It is a 1996 Pontiac Grand Am SE with a 3.1 liter engine.  The car has been setting up for a number of years. When I tried starting it the fuel pump assembly had to be changed.  It is now running, but the instrument cluster is dead.  The tach, speedometer and temperature gauge indicators are not working. The check engine light stays on. It was brought to a local AutoZone for an OBD II test.  All that was found was a code 03. I really don’t think they did a complete test. I tested all the fuses under the hood and in the dash.  There was no voltage to the PCM circuit. The PCM circuit should have voltage at all times and I have not been able to determine why there is not voltage.  I don’t know if this can cause the cluster not to work.  I have a wiring diagram for this vehicle but your help would be greatly appreciated in letting me know which circuits to test. I can email you a copy of the electrical diagram if it would help you to troubleshoot my problem.
Thanks,
Raymond email: rayloisflory(at)hotmail.com


ANSWER: The pcm must have power otherwise the car will not run.Code 03 means nothing as any obd2 engines will begin with a p number and then the code.When you say the cluster doesnt work,do you mean register any temp,speed and rpms?You will need to read off all the codes and go from there.A cheap scan tool is available to read the obd codes.2 possible causes are speed sensor fault and temp sensor.These 2 sensors work the clusters.

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QUESTION:  First let me say thanks for your help. You asked > When you say the cluster doesnt work,do you mean register any temp,speed and rpms ? Answer : I mean that the fuel,alternator, temperture guages along with the rpm tachomentor and the speedomentor do not register any thing.All the cluster lights seem to light when I turn the ignition switch on and when I start and run the engine theall the gauges register 0.

ANSWER: You will need to remove the cluster and see if there is power to the unit.It will have a plug in or possibly 2 plug ins to the cluster.Is this a digital cluster similar to the cadillac?

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QUESTION: 1-12-09
..... No this not the a digital dash panel. I have it removed and there seems to be 1 plug with I'll say 3 wires pluged into the cluster and another larger black connector with a bunch of wires into the conector that has at least a dozen rond pin hols in it., this is a large harnes to this black plug. What also puzzels me is that on my wireing diagram it shows that I am to have power at all times at the 10 amp fuse on the fuse block under the hood that is marked PCM for that fuse, I DO NOT get any power on either side of this fuse and I dont know what this is to be feeding power to.Maybe this is the reason when Auto Zone put the OBD to this car they only told me about a o3 code and that was all they found when every instrament does not operate. I cant let my grandson drive it with out being able to know the speed he is going or see any of the clusters working. Thanks again.... Raymond

Answer
You will need to read the codes to find out what is making the check engine light come on.Then you can go from there.I suggest going to a shop and have them look at it.Ask them to list all codes.If they cannot read the codes then you possibly have a fault in the pcm.