BCM Question??

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Mar 15, 2007 | 06:21 PM

TN94Z

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BCM Question??

Does the BCM have any effect on the gauges? My gauges are all of the sudden not working. I have checked the fuse. I recently had an issue with my BCM not sending a ground to my starter relay. Could this be the same issue with the gauges?

Mar 19, 2007 | 10:22 AM

TN94Z

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Anyone? The cluster is getting power because the seatbelt light and the security light flash occasionally. But the guages just don't work.

Mar 20, 2007 | 12:21 PM

01WS6/tamu

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All of the cluster information is serial data from the data bus. The tach and speedo are the only hardwired functions from the pcm the rest are serial data. It could be a ground issue more than likely . Go back and check all of the grounds on the back of the block. However, if there is something internally wrong with the bcm and it is killing class 2 serial data communications that could be your whole problem right there.

Mar 20, 2007 | 12:34 PM

TN94Z

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So it gets the serial data from the BCM? That probably is the problem then

Mar 25, 2007 | 02:35 PM

TN94Z

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Is there any way around this issue without getting a new BCM? This is a race car only.

Mar 25, 2007 | 05:10 PM

sreve

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gm makes a habit of mounting the bcm on the ac\heat plenum although it has a weather pack connector green pins are pretty common.
another thing to check.

Mar 25, 2007 | 10:20 PM

01WS6/tamu

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No all of the modules are on a databus circuit like what is used in a computer network system like an office has. If the bcm is going bad it can short the buss to ground and kill communications hence your gauges not working. But check the friggin grounds before you start changing parts.

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Mar 25, 2007 | 10:39 PM

TN94Z

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The only grounds that were messed with were the ones on the block and they have been put back. The reason i suspect the BCM is the original problem. I had some wires shorted out. Then the car wouldn't start. I jumped the post on the starter relay and it cranked. I then jumped off the wire that gives the starter relay its ground to a constant ground which comes from the BCM. That is why I think the BCm is the problem. I can get another one for free but of course it will have to be programmed for my car. But I will check the grounds again.