89 k2500 speedo

[brian617]

88-89 C/K1500 DRAC is integrated into speedo cluster. 90-up they are right behind the glove box insert.

[hammertime371]

ok great info guys thanks!!

[hammertime371]

what would be the better way to go since the gear ratio and tire size is not going to be stock so recalibrating will be nessary...so should I get the vssb from the 90 and up and do the dip switch mod or is there a better way to get this done??

[buddrow]

88-89 C/K1500 DRAC is integrated into speedo cluster. 90-up they are right behind the glove box insert.

FYI, the DRAC didnt appear until either late 90 or 91 model years. My 90 is all in the cluster, no DRAC. Possibly a bad solder joint or loose wire.

Buddrow

[EagleMark]

Long ago there were some parts available from GM to slide into dash cluster and adjust speed, there's some pistures and copies of GM papers on it here somewhere... not that the parts are available anymore but might give info to adjust, like you do with DRAC/VSSB.

[buddrow]

Ya Ive had mine apart and it looks like there are jumpers just like the DRACs have, just figuring out which ones to change. The instrument connector at the dash are different on the earl trucks compared to the normal GM type connectors as well. Could be poor connection there or as was stated earlier a bad solder joint since the dash smacking has an effect on operation. :) Although I have seen the wires(insulation) at the VSS connector that degrade overtime and cause erratic VSS signal as well.

Buddrow

edit:

You should verify the cluster connector on the harness to whatever year you replace it with. As I mentioned my 90 has the early style connector and is different from the 92 I know for sure but dont have a 91 available to look at.