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Username Post: GM BCM Swap        (Topic#362457)
Posts: 316
Age: 32
Loc: Tennessee
Reg: 02-22-04
09-05-20 11:46 AM - Post#2802836    

These aren't specifically Chevy branded cars I'm working with, but they are GM so I'm hoping someone here can help.

I'm working on a 1988 Oldsmobile Toronado, which seems to be kind of rare (at least where I am) because finding parts specific to these cars seems next to impossible. It has the digital gauge cluster, which sometimes fails to turn on. The odometer reads "Error" and the dash intermittently reboots the A/C controls. The cluster also reads "Electrical Problem", which seems obvious at this point.

Some research indicates this seems to point to a faulty BCM, which is part number 1227333. Ideally it is recommended to swap with a BCM from an identical car, but that has proven to be impossible. So, I picked up a BCM with the same part number that was pulled from a 1986 Cadillac Seville.

Directly swapping these yielded what you might expect, the A/C controls read blank and the gauges don't work. There are two EEPROMs located under a panel on the top of the BCM, so I swapped those between the old and new modules. Now the BCM I picked up from the Cadillac works as expected with the car, but the problems seem to have followed the chips; it now behaves identically to the issues with the old BCM.

I can't find any information anywhere on swapping GM body control modules this old, but ideally I would think it would be pretty simple considering the age. I'm pulling this hypothesis out of my butt, but is it possible one of these chips stores the actual vehicle control programs and the other is used for storing sensor readings? If so, which is which, and would it be possible to install the Toronado programming chip and the Seville memory chip into a BCM? I'm hoping if that is the case, perhaps the original memory chip got corrupted and replacing it with another one might fix it.

I could use any tips and advise available. I don't think the fault is with the gauge cluster, as if I start pressing buttons on the dash it will sometimes just come on.

My Chevys (I.E. What I'm Asking About)
------------------------- -------------
-1988/1989 C/K1500 5.7L w/700R4 ('88 C Body, '89 K Everything Else)
-2003 Avalanche Z71, Auto, 4x4


Frequent Contributor
Posts: 1531
Age: 61
Loc: Murphy N.C.
Reg: 01-25-14
10-03-20 04:57 PM - Post#2804753    
    In response to Majoraslayer

Not sure this will help and it's been so long now but I don't remember what year it was. Sure it was that era Olds digital dash that had resistors that fell off the cluster board. Replaced them with Radio Shack "yea that long ago" and all was good. I found the cure on the interweb. You may try that in a search.


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