1990 K2500 Speed Sensor Issue

[NChristian9]

I have a 1990 K2500 that is constantly shifting back and forth at highway speeds. Speedometer is intermittent and seems to jive with the shifting. I’ve replaced the speed sensor in the transfer case which made no difference. This year model has the drac integrated into the instrument cluster. I’m inclined to think the issue is a bad instrument cluster but wanted to get input here. Anyone else have this issue and have a solution? Appreciate the input!

 

[someotherguy]

You're on the right track thinking the problem is in the cluster. I've seen this happen on a few of the 88-91 trucks. Most likely it's bad solder joints in the cluster or possibly as simple as oxidation on the connector pins. I haven't personally dug into one to fix this particular issue, but I think I would start simple - remove the cluster and spray the connector pins liberally with DeOxit contact cleaner, see if that helps.

Richard

 

[Schurkey]

Perhaps a moderator will move this thread out of the ENGINE section, and into OEM + Custom Interiors, perhaps.

My '88 had a faulty instrument cluster (DRAC). When the speedo died, so did the torque converter clutch, odometer, cruise control, ABS, and since the computer had no speed reference, it would light-up the MIL.

If all those items aren't failing when the speedo dies...it's not the DRAC or the speed sensor.

 

[NChristian9]

Perhaps a moderator will move this thread out of the ENGINE section, and into OEM + Custom Interiors, perhaps.

My '88 had a faulty instrument cluster (DRAC). When the speedo died, so did the torque converter clutch, odometer, cruise control, ABS, and since the computer had no speed reference, it would light-up the MIL.

If all those items aren't failing when the speedo dies...it's not the DRAC or the speed sensor.

What was your fix? Did you put an aftermarket cluster in? My abs, odometer and cruise are having issues as well.

 

[Schurkey]

I went to the Treasure Yard, and got an entire instrument cluster from a similar vehicle. (Actually a GMC, I guess--the gauges were styled a little differently.)

'Course, the fuel gauge on that cluster was faulty, so now I have my original fuel gauge in the new cluster. The styling doesn't match, but they all work OK.