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'94 Speedometer and Odometer Not Working

The truck is still at the speedometer shop and it's providing a challenge to the pro on this. Definitely in the wiring. I will print off the above trouble shooting and bring it to him on Monday.
 
The speedometer repair shop finally figured out the speedometer problem. When my son pulled the Driver's side door panel to do the mirror installation, he pulled the plug from the window switches and one of the female ends stayed on a male end. He separated them, but was not certain what slot it went into. So there was a grounding short there which caused the window to not work, switches got hot and it was also impacting the gauge cluster. He's got it working, but the speed is inaccurate (he tried both the '94 and '95 VSSB) so that is now being re-calibrated and we'll pick it up later today.

Based on the number of butt splices on the wiring, there must have been some prior work done on this.
 
Final follow-up. Due to the inaccuracy of the speedometer and the inability to adjust it close enough with the VSSC (aka DRAC), the shop installed an Electronic Ratio Adapter from Abbot industries. This can be adjusted in the future for whatever tire size we put on it. The shop will do that for free and it takes just a few minutes to flip some DIP switches.

Dash is back together and we're in the process of installing the 4 position tune. Truck is running great.
 
I don't understand how a door short takes out the speedo. The window must have been on the same fuse or something as the speedo/odo drive.

Course the coolant temp switch took out the gauges fuse with a dead short and wasn't fun to hunt down.
 
WarWagon said:
I don't understand how a door short takes out the speedo. The window must have been on the same fuse or something as the speedo/odo drive.

Course the coolant temp switch took out the gauges fuse with a dead short and wasn't fun to hunt down.
Click to expand...

The guy at the shop was saying basically the same, that the windows were on a different circuit. However the short in the windows was on the ground and apparently that went into the gauge cluster. All the gauges would dip when you pressed the window button and the speedo would spike to red line. It doesn't explain why the speedo was not working in the first place. This is the original cluster, odometer and trip meter (it's working). Also don't understand what was changed to require the Electronic Ratio Adapter.
 
That makes some sense. Did they disassemble and clean that ground? Course you would be at the current limit of the wire causing a voltage drop maybe... But that should have burned the wire out.
 
I did not create the short, my son did when he pulled the plug for the window switches. He said that a female connector pulled out of the plug and stayed on the male connector. He pulled those apart but was not sure he got the female connector back into the right position and that is what was causing the short. I've never been inside that door.

I hate trouble shooting wiring. It's random guessing for me.
 
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