Hi All, time for my first mod of the Labor Day Weekend.
Been suffering without a full set of gauges in the '90 Bonneville LE, so this afternoon and evening was spent grafting an SE'* instruments into an LE housing. (No, it'* not easier to just swap panels...the body connector is different and no gearshift indicator on the speedometer.)
Here'* the original gauges in the car: Nothing exciting, just speedo, fuel, coolant temp, and some idiot lamps.
Here'* the front of the Instrument pannel after removal:
And the back with the original mylar circuit board in place:
The basic problem is that I can't just transfer the panels I want in place of the pannels in the existing ip cluster. The way GM made it, the panels are in pairs with the "System Monitor and Odometer" panels as one piece, "Speedometer and Fuel Level", and "Coolant Temp and Light Monitor". The housings themselves are also different. The basic form is the same, but the circuit boards, dividers, and terminal placement are different enough to prevent parts swapping.
So, I proceeded to cut out the panels and graft them together. It'* actually pretty easy. Score the seams front and back with an Xacto knife, dremel away the thick plastic "illuminator" strip between the Speedo and Tach pannels, then snap the plastic. You end up with this:
The housing itself needs to be modified too. But this is just a matter of cutting new holes for the teminal posts of the gauges. I also cutaway the circuit traces that were in the way and soldered new wires for the circuits. End result is the back of the cluster looks like this:
You can see the wires on the right reconnect the gauges that moved, as well as the new Tach Buffer circuit, Oil Pressure, and Voltmeter circuits.
And here'* the finished IP ready to go in the car. I used electrical tape to keep light out of the seams between panels. Works OK, but on the next try I'm going to cut styrene plates and glue the pannels together the same way as the originals (in pairs). By keeping the original LE end panels, I still have room to add a boost pressure gauge as well as a bottle pressure gauge. If I can find Analog gauges small enough, might add a fuel pressure gauge too. (looks like I can fit two on the far left, and one on the far right of the IP)
Put it back in the car about a half hour ago and took it for a spin. Works good. Tomorrow when I have some daylight, I need to add the circuits for the tach and an oil pressure sender to the car'* wiring.