Idoit Light to factory gauge swap

[dougfather]

I have an 84 GP with the original warning lights and clock. I bought a factory gauge pack and factory tach at GM Carlisle show a year ago.

Aside from changing the sending units, is there any changes in the wiring harness that I need to know about? I have the the factory shop manual and parts manual, but nothing that I have found so far spells out the differences.

 

[pontiacgp]

there's no difference in the wiring and the only sender unit that has the be changed is the oil sender unit. (if my I remember right) You can get an aftermarket sender unit for less than half of the original at the dealer but I have found the aftermarket units to be a little longer than the original which causes interference with the linkage to the transmission from the column. You can get around that by putting a 45 degree adapter to position the sender unit to provide clearance from the linkage. You can put the aftermarket unit in without the adapter but you'll find the conector gets knocked off by the linkage expecially if you put the transmission in 1st gear.

 

[85_SS]

I did this swap years back on my parent's Cutlass. On that car, some of the pin locations had to be changed, but on some cars you get lucky and they used the same locations. You can trace the cct board on both to see where they go now and where they need to go. You will have to run your own tach wire, and yes you will need sending units for both coolant and oil pressure.

 

[dougfather]

I have read somewhere that the Cutlass required the swap. I wasn't sure about the Grand Prix. The circuit board looks the same from what I can tell.

 

[srercrcr]

The GP is all set up for the tach. If you have a clock now, you'll just need to change pins.