1985 Ford Crown Vic LTD 302ci 4dr Sedan Speedometer Issue

[Paul Anthony]

Hi All,

I just became a forum member. I am looking for counsel on how to identify an issue with a non working speedometer on my 1985 CV.

I have recently completed various repairs on my 66K miles CV.

 

The speedometer and cruise control all once worked. Then the cruise control stopped working. Some time after, the speedometer stopped working. I checked the cable connection behind the dash. It "feels" ok.  However, I have yet to pull the dash unit. (not sure how).

 

I am asking on how to best isolate this issue. I think the cable is spinning internally but not sure. Should I pull the dash init (how to do) and observe for a spinning interior cable while driving?

 

Could this be a simple bad connect between the speedo cable and the speedo head unit? I suspect that the cruise operates off the speedo function but not sure. What is the control for cruise on a 1985 CV? Is it a vacuum function?

 

Also, any reccomendations for a good shop manual (find on line) that would be very helpful for diagnosing 85 CV issues?

 

Any thoughts/ suggestions are greatly appreciated.

Thanks,

Paul Anthony

[Bloo]

Start at the transmission and follow the cable. Probably there is a cable from the transmission to a sensor for the cruise under the hood somewhere, and a second cable that continues from that sensor to the speedometer.

 

The cruise control probably does use vacuum, but it probably only uses vacuum to pull the throttle.

 

[ABear]

Is the odometer working?

 

Odometer if mechanical is, driven by the same cable as the speedometer, if digital odometer the back of the speedometer may have a sensor and that sensor would be used for odometer and cruise control, that sensor is turned by the speedo cable..

 

If you have a helper, you can remove the cable from the transmission, remove the gear (held on by a clip, don't loose the clip as it is needed to keep gear on the cable). Then you can use a drill at low speed to turn the inside core.. Have helper observe if Speedo and odometer work while drill is turning..

 

Some vehicles use a short "jumper" between the speedo and the sensor so it may not be directly attached to back of the instrument cluster.

[Paul Anthony]

Thanks Bloo and ABear! I will follow through!