Electronic speedo testing

[niceolddart]

I know it's not an A Body but, I have a very nice instrument cluster out of a 90 Ramcharger I'm parting out. I would like to confirm that the electronic speedometer is working properly. I have it, along with the whole wiring harness & VSS assembly removed from the truck. How do, or can I check the operation of it? I have the same question posted on FTO but haven't heard anything yet. Any help would be appreciated. TIA

 

[Dana67Dart]

I would think it will depend on the way it works.

If it is electro mechanical as in the sender directly converting rotating energy to electrical and then causing the needle of the speedo to move.

Vs

If it is 100% electronic the sender converts rotating energy to electrical (pulses, voltage, etc.) and then sends that info to the computer, the computer converts the input to a signal that causes the needle of the speedo to move

The first way you might be able to hook the sender to the speedo then spin the sender

Second way the computer and most of the wiring would have to be hooked up and the computer would need to know the engine is running, and then the sender would need to be spun.


There are guys who have the tools and knowledge to make the computer think all those things are working and can send a signal to the speedo thatched sender is going 70 mph ( for example)

Lastly a speedo shop should be able to know how to test it.

Good luck to you

Let us know what you find out.

 

[niceolddart]

I would think it will depend on the way it works.

If it is electro mechanical as in the sender directly converting rotating energy to electrical and then causing the needle of the speedo to move.

Vs

If it is 100% electronic the sender converts rotating energy to electrical (pulses, voltage, etc.) and then sends that info to the computer, the computer converts the input to a signal that causes the needle of the speedo to move

The first way you might be able to hook the sender to the speedo then spin the sender

Second way the computer and most of the wiring would have to be hooked up and the computer would need to know the engine is running, and then the sender would need to be spun.


There are guys who have the tools and knowledge to make the computer think all those things are working and can send a signal to the speedo thatched sender is going 70 mph ( for example)

Lastly a speedo shop should be able to know how to test it.

Good luck to you

Let us know what you find out.

Thanks for your input on this, I appreciate it.

 

[67Dart273]

It might be a step motor type deal. Sorry. Know nothing about them.