I have a 93 seville, pre northstar, while driving the fuel economy readout on the left and the heater/ac readout go to dashed lines and non of the buttons work. The problem will correct it self in time but will return at any time. Any ideas of where to look for a problem?

Its a bad IPC/cluster.....or one of the computers on the car is corrupting the data on the UART data line circuit 800.

These can be very hard to find if intermitant. My '93 took two weeks to pinpoint the cluster. I found if I pressed and held the cluster harness plug in a certain way for 30 seconds....I could induce the failure mode. Bad cluster/IPC.

The GM/Delco cluster diagnostic terminals appear to not test circuit 800 failures. My cluster tested 'OK.' To them '--' is a normal OK mode. I had to show the failure mode in the car to the Delco tech. He was like ......oh crap.....we dont test for that.

So...in some cases its taking 3-4 'rebuilt' clusters to clear up the 'loss of data', defrost lamp, '--' error, failure mode.

The IPC/cluster is $300 exchange from Delco radio/speedometer repair shops.


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