1992 chevy Blazer gauge cluster

[Buick City]

This isn't an antique,but as soon as I can fix this problem I can sell this ,and put the money in my antique cars! The problem is some times when I turn the key , all the gauges work , and sometimes they don't ! When they don't work , the only thing that lights up is the mileage and head light picture " for running lights ". When they work ,everything works (except the tach - but it still lights up ) I tried another gauge cluster , but nothing lit up on it ! It is the kind that has the female part of the harness attached to the metal part of the dash frame. I thought it might have a BCM like my Reatta, but can't find it in the shop manual. Any help on this will be appreciated ! THANKS !

[Larry Schramm]

I do not remember the 92 Blazer having a BCM.

That said, my first guess is it probably is a bad ignition switch.

Two questions, 1. How many miles on the vehicle?

2. Did this car have an owner that put 5 pounds of junk on a key chain attached to the key that went into the ignition?

That would lead to an ignition switch also.

Also on putting in a different cluster with one partially working and the other not working many vehicles of that vintage had a number of clusters that looked the same but if you did not have the EXACT PART NUMBER that you exchanged it with it would not work. Look at the label on the clusters and see if they have the exact part numbers.

For the tachometer, if you have a scanner look to see if you have a tach signal. That signal comes from the ECM and is then transferred to the cluster by a serial data line.

I think I have all of this right from memory.

[Buick City]

Thanks Larry ,the vehicle has 225,000 miles I don't know the history ,but you are right ,as the part # was diff,even though they looked alike (one ended with 45 , the other with 65 ) - only has ECM , but 2 circuits go to the cluster . I might go back to the bone-yard and dig out the ECM that goes with the cluster I have! The ign switch is located mid-way on the steering collum , just the ign lock with key turns a rod that moves the switch. Thanks for responding!