Need help with transmission/speedo wiring.

[ben2go]

Truck is an '89 2500 with a 5.7 with what is supposed to be a 700r4. There is a wiring connector on the back of the transmission on the driver side with what looks to be around 7 wires in it. The speedo quit working but the odometer still works. At some point something has hit the connector and crushed it. Could this cause the speedo to quit and the odometer to keep working? Is there a wiring diagram around for this connector?

On another trans related note. If this trans isn't electronic, why no cables on it except what I think is a kick down cable? Do these transmission not have a lock up torque converter?

 

[Frank Enstein]

There should be a square 4 pin connector on the driver's side above the pan gasket. That is for the lockup.

The speedometer sensor must be working because the odometer wouldn't work without the sensor.

I am not very familiar with the 89 gauges. I believe there is something in the cluster that buffers the signal.

I think the problem might be in the cluster. For now use a gps speedometer on your phone until somebody who knows more chimes in!

 

[Erik the Awful]

On another trans related note. If this trans isn't electronic, why no cables on it except what I think is a kick down cable? Do these transmission not have a lock up torque converter?

On a 700R4, one of the wires on the 4-pin wiring connector carries the current to the torque converter clutch. It's electrically activated. Also, that's not a kickdown cable, that's a throttle valve cable, and you must adjust it correctly or you'll burn up your transmission.

 

[ben2go]

There should be a square 4 pin connector on the driver's side above the pan gasket. That is for the lockup.

The speedometer sensor must be working because the odometer wouldn't work without the sensor.

I am not very familiar with the 89 gauges. I believe there is something in the cluster that buffers the signal.

I think the problem might be in the cluster. For now use a gps speedometer on your phone until somebody who knows more chimes in!

On a 700R4, one of the wires on the 4-pin wiring connector carries the current to the torque converter clutch. It's electrically activated. Also, that's not a kickdown cable, that's a throttle valve cable, and you must adjust it correctly or you'll burn up your transmission.

Thanks you guys. No transmission problems but the odometer quit work on my son last night. I may have to install another cluster. I'll look around to see if I can find repair info and try to keep the OE cluster.

 

[PlayingWithTBI]

I am not very familiar with the 89 gauges. I believe there is something in the cluster that buffers the signal.

Yes, the VSS sends the signal to the VSSB signal converter on the back of the cluster, there's no separate DRAC on 88-91 clusters. I had the opposite happen to me, the odometer quit but the speedometer worked. It was in the cluster, I went with a Dakota Digital gauge set. Scroll down to the bottom to see options for your 89.

1973- 98 GM Trucks

Dakota Digital manufactures digital instrumentation and accessories for the automotive, motorcycle and car audio enthusiast.

www.dakotadigital.com

 

[ben2go]

Yes, the VSS sends the signal to the VSSB signal converter on the back of the cluster, there's no separate DRAC on 88-91 clusters. I had the opposite happen to me, the odometer quit but the speedometer worked. It was in the cluster, I went with a Dakota Digital gauge set. Scroll down to the bottom to see options for your 89.

1973- 98 GM Trucks

Dakota Digital manufactures digital instrumentation and accessories for the automotive, motorcycle and car audio enthusiast.

www.dakotadigital.com

Thanks. I'll check them out.

 

[Schurkey]

1988 K1500 ('89 probably the same.)

VSS signal goes to instrument cluster. Bigass integrated circuit assembly modifies the signal, sends it to speedo, odo, cruise, ABS, and computer. If the cruise or ABS still works, if the computer still has a vehicle speed input, you've got a problem with the speedo and/or the odo, not the instrument cluster itself.

My truck had the opposite problem--speedo, odo, cruise, ABS, and computer all lost their signal and quit working, all at the same time. I had to replace the instrument cluster to get a functional bigass integrated circuit assembly.

 

[Mathies]

1988 K1500 ('89 probably the same.)

VSS signal goes to instrument cluster. Bigass integrated circuit assembly modifies the signal, sends it to speedo, odo, cruise, ABS, and computer. If the cruise or ABS still works, if the computer still has a vehicle speed input, you've got a problem with the speedo and/or the odo, not the instrument cluster itself.

My truck had the opposite problem--speedo, odo, cruise, ABS, and computer all lost their signal and quit working, all at the same time. I had to replace the instrument cluster to get a functional bigass integrated circuit assembly.

When this happenend did the truck start?

 

[Leeztruk]

One thing to be aware of with the '88-'91 clusters. The circuitry of the cluster is specific to a rear end gear/tire size for correct speedometer reading. You can just replace the speedometer head itself without changing the rest of the cluster. This is one I have sitting on a shelf. It's a simple plug-n-play after you take the cluster face off of the cluster body

 

[Leeztruk]

I just looked at the dates on the first posts. Don't think we're gonna get a response after two years passage