I Have a 1980 GS. My speedometer was working fine. All of a sudden its working erratically. It oscillates up and down. I think it is a bad speedometer cable but Im not completely sure. If it is the cable, Any one knows were to get the speedometer cable? Thanks in advance

 

It's not a odometer, it is a "Speedometer". :-)

Place a WTB thread in the classifieds.

 

Chances are that it's not the cable but the speedometer/odometer itself. Mine started working erratically and making bad noises. I unplugged the cable from the transmission and now drive by the tachometer.

 

Speedo cable is easy enough to test;

1) visually inspect for kinks, cracks, or crimps, from the trans all the way to the speedo.
2) unclip cable from the back of the speedometer, and without pulling the core out, turn it manually and see if you feel tension (it shouldn't freewheel; it's attached at the trans)
3) disconnect the other end from the trans too, and see if the cable turns smoothly with no binding or jerking.

I've never tried this with the RX speedo cable, but some can be cleaned out and re-lubricated by manually pulling the core out.

 

Any ideas as to where can I find a replacement cable? I've tried Mazda but its no longer available.

 

as Doc said, post a want to buy ad in the 1st gen for sale/wanted section. verify that the cable is bad before you go chasing gremlins. often times the cables will bind up inside of the sheath and cause erratic readings. pull the cable from the trans and slide the cable itself ouf of the sheath and inspec it.

 

I have a 1980 also, and recently started having trouble with my speedo. Worked fine last summer, but since it's gotten cold, it is irratic and makes noise until the heater warms things up. Now the odometer has quit, so I need to replace it.

The best way is to purchase another first generation instrument cluster through this forum. If you want the colors to match, then buy a 1979 or 1980 cluster. If you don't care about color, a later model 1st gen will do.

You can keep your old instrument cluster and just salvage the speedo from the one you buy. It is totally mechanical and is easy to replace without affecting any of the cluster's electronics.

Remove your cluster from the car and then remove front cover from both instrument clusters. Remove the 2 screws on the rear of the speedo that are located on either side of the cable socket. The complete speedo and face can then be gently removed from the front of the cluster.

Reverse the process to replace the broken speedo in your original instrument cluster and re-assemble your dash.

The replacement speedo should work fine now.

 

There must be some electronics/sensors in the speedo because my cruise stopped working when my speedo failed.

 

Where does the cruise control speed sensor live? I don't believe cruise became available until 81...?

 

Thanks for the info...

 

Affirmative.

No cruise control in a '79 or '80.

Later model 1st gen speedos have a light for something (a sensor or indicator of some kind) at the bottom of the gauge. However, since the '79/'80 doesn't have it, you can still use the later speedo and can ignore the indicator because it won't ever come on.

 

To find a new cable if you do need it, Apex Auto Parts, they have new and used last time i checked.