BCM/Guages Question???
03-27-2007, 08:36 AM
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BCM/Guages Question??? I had a BCM issue recently and now my gauges won't work. I know that if you swap out the BCM it must be programmed for your car/key specifically. My question is if I swap out my BCM for another BCM should this allow my guages to work?(Which won't work with my current BCM) I know the car probably won't crank, but would this be a good test to see if the BCM is what is causing my gauges not to work? I can get a used BCM from a buddy for the test.
03-27-2007, 09:48 AM
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Yeah, it is just happened at the same time. If there is anyway that the BCm could stop the gauges from working then I think that is it. I have changed clusters and checked grounds and the BCM is about the only thing left that I have had problems with. Plus it is a free test so i can't really go wrong. At least that would rule out the BCM if it didn't fix it.
If it is killing the databus, would the gauge just be reading crazy or not reading at all? My guages do not work at all, but the security light flashes and the seatbelt light flashes...so I know they are getting power.
If it is killing the databus, would the gauge just be reading crazy or not reading at all? My guages do not work at all, but the security light flashes and the seatbelt light flashes...so I know they are getting power.
03-29-2007, 08:51 AM
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One other question: Say for instance, I swap out the BCM that my buddy has and my gauges start working again. Now my car is a race car so i don't really care about the VATS. Assuming that the new BCM has a different resistance than what my car has, can I not just check the resistance chip in my car and the resistance chip in the key from his car and make a note of each. Then find a resistor that matches his key and bypass my VATS with a resistor of the same Ohm reading? I hope I didn't ramble too much and that makes sense to someone.
03-29-2007, 11:35 AM
#5
If the car we are dealing with is the 98 i your sig then all of the gauges are the old style non databus controlled. The instrument cluster does have multiple ign inputs though. So if you have a problem in that area it can also effect the bcm and vats system.
03-29-2007, 01:45 PM
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So are you saying that the BCM will not have any effect on the gauges not working or will? Other than grounds, what else do you suggest I look at? I am going to dive into it more tonight. I have been having to use my HPTuners to see what the car is doing...but that doesn't help the fuel gauge!! You are helping alot. Thanks man!
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03-30-2007, 07:29 AM
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Well, I tried to swap out the BCM for a different one just in case and the guauges still didn't work. Do you happen to have a schematic of the wiring that is involved with the gauges? Are the only grounds that would effect it on the block? I have 3 grounds(I believe) grounded to the back of the drivers side head. The pass. side head is grounded to the frame...
03-30-2007, 10:34 AM
#10
I do but it will be tomorrow before I can get it to you. I have alldata at the shop. Yes you can junk all of your stock gauges, have the vats deleted from the pcm and bypass the starter enable relay and it will work fine. Then VATS is fully disabled and there is not any bcm intereference with the vehicle function.
03-30-2007, 10:44 AM
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Thanks. If you can, get me that schematic whenever you get a chance. That way I can start at one end and work my way through checking everything.
03-31-2007, 03:27 PM
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Well, the gauges are working now. I was wiring up the wideband and rewiring my trans brake button and decided to check the gauges fuse for the third time. Pulled the fuse out, looked good as it always has, put it back in and the next time that I cranked the car the gauges were working. I don't know if the fuse just wasn't making good contact or what, but they seem to be okay now. I swear me and my buddy had checked that fuse 3 or 4 times with no luck. Who knows? Thanks for all of the help.