Like many of us, the odometer on the original VDO speedometer was shot. It would sometimes work, sometimes stick and often just sit there. for older cars, this may not be an issue, but I wanted to know simple things like, how far I traveled and when to change the oil. While I was lucky to have an MPH speedo, many of the imported G's from the 80's, feature Kilometer measurements. Here is a quick and easy solution for many of us.
For the purest, it would be best to send your speedo off for repair. There are many good resources that repair classic speedometers and the original VDO unit is very nice. In my case, I wanted an upgrade.
A quick search of available VDO gages and you will find nice digital VDO gauge that will fit directly in the existing cluster. I settled on a VDO Vision Black 85 MPH/130 KpH Speedo (12/24V) - 3 3/8" - Vision Black model number 437-152. The bonus is that for those of us who have 24v G's this gauge will work!
For those of you who think a 120 MPH gage is better, think about it for a second. These trucks rarely go over 70 much less 85.
I ordered the sender and the gauge from eGuages.com. The bonus is the new speedo is only about $130!
The old gage worked by a spinning cable that comes from the transfer case to the back of the old speedo. The new unit, however, is 100% electronic. An electronic pulse is required to measure the speed of the car. The speed can be picked up by a pulse coming from any part of the drivetrain after the transmission.
It is very easy to access the cluster. Two screws one on each side then the back cover comes off. Simply unscrew the cable, remove the lights and you push the old speedo out of the front of the cluster. then I took the rubber surround from the old speedo and put it on the new one and slid it in.
The wiring instructions come with the new speedo, the only strange thing is the new speedo does not have a blinker light. That is not a big deal, I just wired the blinker indicator to the one on the sash luster and I was all good.
Then came the hard part. Getting some sort of speed signal to the new speedo. Let's just say I found it impossible to find an adaptor that would fit the pulse generator to the existing speedometer cable or transfer case. I was lucky because when I followed the old speedometer cable I found an electronic sensor connected to the cable under the dash. At one point my G must have been equipped with cruise control, so I wired the connectors to the new speedometer and while it did not register the correct speed, it did work.
The wiring was pretty simple. as follows:
12V constant to Pin 4
Ground to Pin 3
Existing Sensor to pins 7 & 8
Dash lights to the Light Sockets
I had replaced my dash lights with LED lamps to I updated the lamps int he speedometer to match the LED color I used the the rest of the gages.
All that was left was to calibrate the speedo. I downloaded Ulysse Speedometer to my smart for reference. Then used the Manual Calibration method to get the speedometer to match the value shown on my phone. The end result was a stock looking electronic speedometer that is reliable and easy to read.
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| Original VDO Speedometer |
A quick search of available VDO gages and you will find nice digital VDO gauge that will fit directly in the existing cluster. I settled on a VDO Vision Black 85 MPH/130 KpH Speedo (12/24V) - 3 3/8" - Vision Black model number 437-152. The bonus is that for those of us who have 24v G's this gauge will work!
For those of you who think a 120 MPH gage is better, think about it for a second. These trucks rarely go over 70 much less 85.
I ordered the sender and the gauge from eGuages.com. The bonus is the new speedo is only about $130!
 |
| Existing Cruise Control Sensor |
It is very easy to access the cluster. Two screws one on each side then the back cover comes off. Simply unscrew the cable, remove the lights and you push the old speedo out of the front of the cluster. then I took the rubber surround from the old speedo and put it on the new one and slid it in.
The wiring instructions come with the new speedo, the only strange thing is the new speedo does not have a blinker light. That is not a big deal, I just wired the blinker indicator to the one on the sash luster and I was all good.
Then came the hard part. Getting some sort of speed signal to the new speedo. Let's just say I found it impossible to find an adaptor that would fit the pulse generator to the existing speedometer cable or transfer case. I was lucky because when I followed the old speedometer cable I found an electronic sensor connected to the cable under the dash. At one point my G must have been equipped with cruise control, so I wired the connectors to the new speedometer and while it did not register the correct speed, it did work.
The wiring was pretty simple. as follows:
12V constant to Pin 4
Ground to Pin 3
 |
| New Speedometer |
Dash lights to the Light Sockets
I had replaced my dash lights with LED lamps to I updated the lamps int he speedometer to match the LED color I used the the rest of the gages.
All that was left was to calibrate the speedo. I downloaded Ulysse Speedometer to my smart for reference. Then used the Manual Calibration method to get the speedometer to match the value shown on my phone. The end result was a stock looking electronic speedometer that is reliable and easy to read.
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