Q: My bcm is not working.

asked by on January 04, 2017

Hi, the original owner of my sedan deville swapped out the bcm for some reason and did not swap the proms. This bcm is bad and has been for some time apparently. I bought the car recently and the climate control and fuel center were out when I bought it. I have tried swapping the bcm with other bcms from junkyards. I believe they have been from compatible years, but I am not positive on whether or not I tried one exactly from 1992... What I want to know is if I could use a bcm/prom combo just from another 1992. Please let me know if anyone knows of a way I can purchase or find a working bcm and prom combo.

EDIT I have found that the bcm in my car did work at one time. So that prom must have worked. However when I try to swap the prom into other units or to use the prom that comes with the bcm from junkyards it will work for a few seconds and then the bcm gets very hot and stops working. It seems the problem is coming from somewhere besides the prom. What do I do?

My car has 120000 miles.
My car has an automatic transmission.

Hello. If the computer is quickly overheating and shutting off then it may be possible that excessive voltage or current is flowing too, or through it, causing it to overheat. This can be caused by wiring issues or by a fault with one of the BCM’s internal circuits. It may also be possible that the computer is faulty and needs to be replaced or repaired. If you are unsure, I would recommend having a professional technician, such as one from YourMechanic, visit your location to diagnose what may be causing the issue.

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